UGC NET Paper 2: Environmental Science 29 Oct 2022 Shift 1 (Previous Year Paper)

The correct answer is liquefaction.

 

Key Points

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Therefore, the correct answer is liquefaction.

The correct answer is Transesterification.

 

Key Points

• Biodiesel is produced using a process called transesterification in which the unwanted glycerin in vegetable oil or fat is removed by chemical reactions involving alcohol, such as methanol or ethanol, and a catalyst.
• The catalyst is usually sodium or potassium hydroxide.
• The biodiesel end product consists of long-chain methyl esters.
• Running straight vegetable oil or recycled grease in diesel engines can cause multiple engine problems and should be avoided.

Therefore, the correct answer is transesterification.

The correct answer is Ammonium ion to Molecular Nitrogen conversion.

 

Key Points

• In the anammox reaction, nitrite and ammonium ions are converted directly into diatomic nitrogen and water.
• Anaerobic ammonium-oxidizing (anammox) bacteria oxidize ammonium with nitrite under anoxic conditions.
• The anammox process is currently used to remove ammonium from wastewater and contributes significantly to the loss of fixed nitrogen from the oceans.
• Anammox bacteria combine ammonia and nitrite directly into dinitrogen gas.
• This allows a new and very efficient treatment possibility of wastewater.
• Large-scale treatment with the Anammox process is very complex in design, operation and maintenance.

Therefore, the correct answer is Ammonium ion to Molecular Nitrogen conversion.

The correct answer is Humic and fulvic acids in humus form hydrophobic colloids whereas clay colloids are hydrophilic in nature.

 

Key PointsConsider the first statement: Humus represents organic matter, dark in colour.

• Humus is dark, organic material that forms in soil when plant and animal matter decays.
• The thick brown or black substance that remains after most of the organic litter has decomposed is called humus.

Thus the first statement is correct.

Consider the second statement: Acid soils are devoid of basic cations.

• The acidity of the soil is due to the predominance of H+ ions over OH– ions, the bulk of H+ ions being held in close association with the clay-organic colloid complex.
• So acid soils lack basic cations.

Thus the second statement is correct.

Consider the third statement: Humus contains cellulose and hemicellulose.

• Humus can be defined as a lingo protein complex containing approximately 45 % - lignin compounds, 35% - amino acids, 11% - carbohydrates, 4% - cellulose, 7% - Hemicellulose, 3% - fats, wax, and resins, 6% - other miscellaneous substances, including plant growth substances and inhibitors.

Thus the third statement is correct.

Consider the fourth statement: Humic and fulvic acids in humus form hydrophobic colloids whereas clay colloids are hydrophilic in nature.

• The polycyclic functional groups of humic acid molecules hold or “chelate” water.
• Humates hold many times their weight in moisture and they are not repellant, even when dry.
• This makes humic acids hydrophilic, not hydrophobic (resistant to or avoiding wetting).
• Natural colour is primarily due to the presence of humic substances classified as humic and fulvic acids.
• These are colloidal, hydrophilic, anionic polymeric compounds which are refractive (non-biodegradable).
• Colloidal clay particles are considered as occupying an intermediate position being neither truly lyophilic (liquid-loving) or hydrophilic (water-loving) nor lyophobic (liquid-hating) or hydrophobic (water-repellent).
• Clay colloids possess the properties hydrophilic because of their hydration.

Thus the fourth statement is incorrect.

Therefore, the correct answer is humic and fulvic acids in humus form hydrophobic colloids whereas clay colloids are hydrophilic in nature.

The correct answer is Karanja (Pongamia pinnata).

 

Key Points

• Karanja (Pongamia pinnata) trees are normally planted along highways, roads, and canals to stop soil erosion.
• It is found as one of the most suitable non-edible oil plant species in India due to its good N₂ fixing ability and not being grazable and eatable by animals.
• It can be grown in water-logged, saline and alkaline soil, wasteland/ fallow land and can withstand harsh agro-climates.
• The seeds of Pongamia pinnata contain 30 to 40% oil which is thick, reddish brown in colour oil known as Pongam/Pongamol/Hongay oil which can be converted to biodiesel by transesterification with methanol in the presence of KOH.
• Areas with good natural populations of Pongamia provide a great opportunity for the production of bio-diesel on a local scale and will be able to source germplasm for the development of the resource.

Therefore, the correct answer is Karanja (Pongamia pinnata).

The correct answer is bioremediation.

 

Key Points

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Therefore, the correct answer is bioremediation.

Explanation:

• Oxidation is the loss of electrons, a gain of oxygen, or a loss of hydrogen.
• Reduction is the gain of electrons, loss of oxygen, or gain of hydrogen.

In the given equation,

• The reactant (1) has the carbon atom which is completely oxidized.
• The product (2), the carbon is reduced, and in (3) the carbon is oxidized.
• It takes place under anaerobic conditions.
• In this process, the organic matter is broken down by a consortium of microorganisms in the absence of oxygen and leads to the formation of digestate and biogas which mainly consist of methane and carbon dioxide.
• Various bacteria are involved in each step of the digestion process.
• The principal reaction sequences can be classified into four major groups: Hydrolysis, Fermentation, Acetogenesis/dehydrogenation (acetic acid formation), and Methanogenesis.
• Species isolated from anaerobic digestors include Clostridium, Desulfovibrio, Actinomyces, Bacillus, Pseudomonas, Desulfobacter, Desulfomonas, Escherichia coli, etc.
• Methane is a flammable gas and sometimes catches fire.

​Hence, option 1 is the correct answer.

The correct answer is a precipitation reaction.

 

Key PointsThe various mechanisms involved in heavy metal interaction with soil are:

• Acid-base equilibrium: If a soil solution is considered an aqueous system, water is always the acceptor and heavy metals behave as donors.
• Precipitation-Dissolution: Under various physicochemical conditions like temperature, pH etc. the process of formation of a precipitate helps in the accumulation of heavy metals.
• Absorbance: This is most effectively shown by clay minerals followed by silicates and organic matter. Humic substances escalate CEC which further helps in the solubilization of heavy metals in soil and also aids the formation of the complexes.

Therefore, the correct answer is a precipitation reaction.

Important Points 

• Since the heavy metals are retained in soil/sludge by all processes including complexation by humic substances in organic particles, absorption onto the surface of mineral particles, precipitation reaction and solubilization in acidic conditions.

The correct answer is The proponent of the development project.

 

Key Points

• Review and licensing is the final check on the quality of the EIA report submitted to obtain a project license.
• Once the EIA report is submitted, designated authorities will usually go through it thoroughly, weighing the methods used, data, interpretations, measures and conclusions to assess the impacts of the planned development.
• Their review will determine whether or not the project adequately addresses major environmental and social impacts and other risks, and whether or not to grant a licence to the project proponents or to request project changes.
• In general, EIA review can be divided into two main types:
• Internal review – Undertaken by the responsible authority or other government agency, with or without formal guidelines and procedures; while this is a relatively low-cost option, it lacks transparency.
• External review – Undertaken by an independent body, separate from and/or outside government agencies, with an open and transparent procedure for public comment; this helps in ensuring high-quality outcomes. The environmental issues and the technical aspects of the proposal will determine the expertise required by a review team or individual.

Therefore, the correct answer is the proponent of the development project.

The correct answer is 'Reduced Emission from Deforestation and Forest Degradation'

Key Points

• Reduced Emission from Deforestation and Forest Degradation (REDD):
• REDD is a climate change mitigation strategy aimed at reducing greenhouse gas emissions from deforestation and forest degradation in developing countries.
• It creates a financial value for the carbon stored in forests by offering incentives to developing nations to preserve forest cover.
• The mechanism rewards countries for measurable and verifiable reductions in emissions compared to a baseline scenario.
• It also promotes sustainable forest management, conservation, and enhancement of forest carbon stocks (expanded as REDD+).

Additional Information

• Clean Development Mechanism (CDM):
• Established under the Kyoto Protocol, CDM allows developed countries to invest in emission-reduction projects in developing countries to earn Certified Emission Reduction (CER) credits.
• Unlike REDD, it is not specific to forest conservation; it covers a wide range of emission reduction projects.
• Global Forest Carbon Mechanism:
• This is not a formally established UNFCCC mechanism; it is more of a conceptual term used for programs that value forest carbon globally.
• Incentive-Compatible Selection Mechanism:
• A concept from economics and game theory, focusing on designing policies or contracts so that participants act in ways that lead to desired outcomes.
• It is not specifically linked to forest carbon or climate change mitigation.

Important Points

• REDD was first discussed in the 2005 UNFCCC Conference of the Parties (COP11) in Montreal and expanded to REDD+ in 2007 at COP13 in Bali.
• REDD+ includes conservation, sustainable management of forests, and enhancement of forest carbon stocks, in addition to reducing deforestation and degradation.
• It is considered a cost-effective and nature-based solution for climate change mitigation, biodiversity conservation, and livelihood improvement.

Explanation:

UNFCCC

• It is the United Nations entity tasked with supporting the global response to the threat of climate change.
• The Convention has near universal membership (198 Parties) and is the parent treaty of the 2015 Paris Agreement.
• The main aim of the Paris Agreement is to keep the global average temperature rise this century as close as possible to 1.5 degrees Celsius above pre-industrial levels.
• It is also the parent treaty of the 1997 Kyoto Protocol.
• The ultimate objective of all three agreements under the UNFCCC is to stabilize greenhouse gas concentrations in the atmosphere at a level that will prevent dangerous human interference with the climate system, in a time frame that allows ecosystems to adapt naturally and enables sustainable development.
• Subsidiary Body for Implementation(SBI) has a role in the assessment and review of the effective implementation of the convention.

 

Hence, the option 2 is the correct answer

Explanation

OCED

• The Organization for Economic Co-operation and Development (OCED) is an intergovernmental organization with 38 member countries, founded in 1961 to stimulate economic progress and world trade. It works on the environment and helps countries design and implement effective policies to address environmental problems and sustainably manage natural resources.

Polluter pays principle

• ​The Polluter Pays Principle (PPP) is a principle introduced by the Organisation for Economic Co-operation and Development (OECD) in 1972.
• The principle stipulates that the polluter should bear the cost of pollution caused by them. It is based on the principle of ‘internalizing’ the external costs of production and consumption, which means that the polluter should pay for the damage caused to the environment by their activities.

Frontier Diplomacy Principle

• From this point of view, the "Diplomatic Bluebook for 1971" (Section 17) discussed peaceful uses of atomic energy, space, and the oceans, and also the human environment, which are more recent problems.
• It provides the guiding principles concerning Institutional Economic Aspects of Environmental Pollution
• The human environment problem and the ocean problem received particular attention in the past year.
• Several basic problems of the United Nations and the international community as a whole have been presented in very clear form through various preparatory stages.

Human rights and Environment principles

There are 16 major principles that govern environmental activities. This includes,

• States should ensure a safe, clean, healthy, and sustainable environment in order to respect, protect, and fulfill human rights.
• It should respect, protect, and fulfill human rights in order to ensure a safe, clean, healthy, and sustainable environment.
• States should provide a safe and enabling environment in which individuals, groups, and organs of society that work on human rights or environmental issues can operate free from threats, harassment, intimidation, and violence.

Principles of environmental protection

It includes,

• Prevention- Experience and scientific expertise demonstrate that prevention must be the Golden Rule for environmental protection for both ecological and economic reasons. It can be implemented through prior assessment of environmental harm, licensing, authorization with conditions for operations and remedial consequences for violation, use of standards, and use of best available technologies.
• Precaution- It is based on the notion that environmental regulations often have to act on the frontiers of knowledge and in the absence of full scientific certainty. It operates as a part of a science-based approach to regulation, not a substitute for such an approach, and in practice, the concept is multi-faceted.

Explanation:

Environment Protection Act, 1986:

• It is an Act of the Parliament of India. It was enacted in May 1986 and came into force on 19 November 1986.
• The purpose of the Act is to implement the decisions of the United Nations Conference on the Human Environment.
• They relate to the protection and improvement of the human environment and the prevention of hazards to human beings, other living creatures, plants, and property.
• The Act also provides for coordination of the activities of various central and state authorities established under other environment-related laws, such as the Water Act and the Air Act, etc.

The Biological Diversity Act, 2002 

• It is an Act enacted by the Parliament of India for the preservation of biological diversity in India and provides a mechanism for the equitable sharing of benefits arising out of the use of traditional biological resources and knowledge.
• The Act was enacted to meet the obligations under the Convention on Biological Diversity (CBD) because India is a party of the convention {meeting}.
• The Act was enacted to meet the obligations under CBD, of which India is a part in 2002.

The Forest (Conservation) Act, 1980 

• This is an Act of the Parliament of India to provide for the conservation of forests and for matters connected therewith or ancillary or incidental thereto. It was further amended in 1988. This law extends to the whole of India.
• It was enacted by the Parliament of India to control further deforestation of Forest Areas in India. The act came into force on 25 October 1980. It has five sections.

The Wild Life (Protection) Act, 1972

• This is an Act of the Parliament of India enacted for the protection of plants and animal species. Before 1972, India had only five designated national parks. Among other reforms, the Act established scheduled protected plants, and hunting certain animal species or harvesting these species was largely outlawed.
• The Act provides for the protection of wild animals, birds, and plants; and for matters connected therewith or ancillary or incidental thereto.
• It has six schedules which give varying degrees of protection.

Hence, option 4 is the correct answer.

Explanation:

The Indian Penal Code (IPC) is the official criminal code of India. It is a comprehensive code intended to cover all substantive aspects of criminal law.

Section 275 - Sale of adulterated drugs

• Whoever, knowing any drug or medical preparation to have been adulterated in such a manner as to lessen its efficacy, to change its operation, or to render it noxious, sells the same, or offers or exposes it for sale, or issues it from any dispensary for medicinal purposes as unadul­terated, or causes it to be used for medicinal purposes by any person not knowing of the adulteration, shall be punished with imprisonment of either description for a term which may extend to six months, or with fine which may extend to one thousand rupees, or with both

Section 276 - Sale of drug as a different drug or preparation.

• Whoever knowingly sells, offers, or exposes for sale, or issues from a dispensary for medicinal purposes, any drug or medical prepara­tion, as a different drug or medical preparation, shall be pun­ished with imprisonment of either description for a term which may extend to six months, or with fine which may extend to one thousand rupees, or with both.

Section 277 - Fouling water of public springs or reservoirs.

• Whoever volun­tarily corrupts or fouls the water of any public spring or reser­voir, so as to render it less fit for the purpose for which it is ordinarily used, shall be punished with imprisonment of either description for a term which may extend to three months, or with fine which may extend to five hundred rupees, or with both.

Section 278 - Making atmosphere noxious to health.

• Whoever voluntarily vitiates the atmosphere in any place so as to make it noxious to the health of persons in general dwelling or carrying on business in the neighborhood or passing along a public way, shall be punished with a fine which may extend to five hundred rupees.

Section 288

• Negligent conduct with respect to pulling down or repairing buildings.—Whoever, in pulling down or repairing any building, knowingly or negligently omits to take such order with that building as is sufficient to guard against any probable danger to human life from the fall of that building, or of any part there­of, shall be punished with imprisonment of either description for a term which may extend to six months, or with fine which may extend to one thousand rupees, or with both.

Hence, option 3 is the correct answer.

Explanation:

The fundamental duties of the Indian Constitution clearly impose a duty on every citizen to protect the environment.

• Article 51-A (g), says that “It shall be the duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers, and wildlife and to have compassion for living creatures.”

Hence, option 2 is the correct answer.

In our Constitution, it is vividly expressed that Directive Principles of state policy are bent towards the ideas of a Welfare State, and a healthy environment is said to be an essential ingredient for the welfare state.

• Article 48-A of the constitution states that the state shall endeavor to protect and improve the environment and to safeguard the forests and wildlife of the country.
• This is the testimony of the Government's awareness of a problem of worldwide concern. Since the protection of the environment is now a fundamental duty of every citizen, it is natural that every individual should do it as a personal obligation, merely by regulating the mode of his natural life. The citizen has simply to develop a habitual love for environmental protection.

The Constitution (Eighty-sixth Amendment) Act, 2002 inserted Article 21-A in the Constitution of India to provide free and compulsory education of all children in the age group of six to fourteen years as a Fundamental Right in such a manner as the State may, by law, determine.

Article 13 states that all laws in force in the territory of India immediately before the commencement of this Constitution, in so far as they are inconsistent with the provisions of this Part, shall, to the extent of such inconsistency, be void.

Explanation:

• Environmental Impact Assessment (EIA) is a tool used to assess the significant effects of a project or development proposal on the environment.
• EIAs make sure that project decision-makers think about the likely effects on the environment at the earliest possible time and aim to avoid, reduce or offset those effects. This ensures that proposals are understood properly before decisions are made.

Decentralization of Project Clearances: It classified the developmental projects into two categories:

• Category A (national level appraisal): projects are appraised by Impact Assessment Agency (IAA) and the Expert Appraisal Committee (EAC)
• Category B (state-level appraisal): State Level Environment Impact Assessment Authority (SEIAA) and State Level Expert Appraisal Committee (SEAC) provide clearance to the Category B projects.
• Category A projects require mandatory environmental clearance and thus they do not have to undergo the screening process.
• Category B projects undergo a screening process and are further classified into B1 (Mandatorily requiring EIA) and B2 (Not requiring EIA).

Stages of Environmental Clearance

• Screening Stage: Screening refers to the scrutiny of category ‘B’ projects seeking prior environmental clearance made in Form-1 by the concerned State Level Expert Appraisal Committee for determining whether or not the project requires further environmental studies for the preparation of EIA for its appraisal depending upon the nature and location specificity of the project.
• Scoping Stage: What effects could this project have on the environment? Which of these effects are likely to be significant and therefore need particular attention in environmental studies? Which alternatives and mitigation measures ought to be considered in developing the proposal for the project
• Public Consultation stage: To ascertain the views of local persons. The outcome of public consultation, which is not a decision-making process, is to be included in EIA and addressed.
• Appraisal stage: Appraisal means the detailed scrutiny by the Expert Appraisal Committee or State Level Expert Appraisal Committee of the application and other documents submitted by the applicant for grant of environmental clearance.

EIA provides,

• A detailed assessment of the planned project and selected alternatives compared to the baseline conditions.
• Qualitative description measuring higher, medium, and low impacts.
• Quantitative description measuring physical values of water withdrawal, sewage produced and pollutants released.

The correct answer is Article 16.

 

Key Points

• The Environment (Protection) Act was enacted in 1986 to provide the protection and improvement of the environment.
• It empowers the Central Government to establish authorities charged with the mandate of preventing environmental pollution in all its forms and tackling specific environmental problems that are peculiar to different parts of the country.
• The Act was last amended in 1991.
• Section 16 of the Environment (Protection) Act deals with the offences bt the companies which states that:
• ​Where any offence under this Act has been committed by a company, every person who, at the time the offence was committed, was directly in charge of, and was responsible to, the company for the conduct of the business of the company, as well as the company, shall be deemed to be guilty of the offence and shall be liable to be proceeded against and punished accordingly.

Therefore, the correct answer is Article 16.

Explanation:

Correlation coefficient

• It is a statistical measure of the strength of a linear relationship between two variables.
• Its values can range from -1 to 1.
• A correlation coefficient of -1 describes a perfect negative, or inverse, correlation, with values in one series rising as those in the other decline, and vice versa. A coefficient of 1 shows a perfect positive correlation or a direct relationship. A correlation coefficient of 0 means there is no linear relationship.
• So, Correlation coefficients will be used to find out the degree of the linear relationship between the age and height of trees

Standard deviation  (σ) 

• The standard deviation of a random variable, sample, statistical population, data set, or probability distribution is the square root of its variance. It is algebraically simpler, though in practice less robust, than the average absolute deviation.
• A useful property of the standard deviation is that, unlike the variance, it is expressed in the same unit as the data.

Median

• It is the value separating the higher half from the lower half of a data sample, a population, or a probability distribution.
• For a data set, it may be thought of as "the middle" value.
• The basic feature of the median in describing data compared to the mean is that it is not skewed by a small proportion of extremely large or small values, and therefore provides a better representation of the center.

The standard error (SE)

• It is the approximate standard deviation of a statistical sample population.
• The standard error is a statistical term that measures the accuracy with which a sample distribution represents a population by using standard deviation. In statistics, a sample mean deviates from the actual mean of a population; this deviation is the standard error of the mean.

​Hence, option 2 is the correct answer.

The correct answer is (Standard deviation/Mean) × 100.  

 

Key Points

• The coefficient of variation (CV) is the ratio of the standard deviation to the mean and shows the extent of variability about the mean of the population.
• The higher the CV, the greater the dispersion.
• The coefficient of variation is useful as it is dimensionless (i.e. independent of the unit in which the measurement was taken) and thus, comparisons between data sets with different units or widely different means.
• The standard deviation is an absolute measure of dispersion.
• The corresponding relative is known as the coefficient of variance.
• It is used in a such problem where we want to compare the variability of two or more series.
• The coefficient of variance is denoted by C.V and is calculated as:
• $C.V = {Standard \ deviation \over Mean}\times 100$

Therefore, the correct answer is (Standard deviation/Mean) × 100.

The correct answer is Blood group type (A, B, AB, O).

 

Key Points

• A nominal variable is a type of categorical variable that can have two or more categories.
• However, there is no ordering within these categories.
• A nominal variable does not have any numerical characteristics and is qualitative.
• A nominal variable can be coded but arithmetic operations cannot be performed on them.
• In other words, nominal variables cannot be quantified.
• Examples:
• Hair colour (blonde, black, brown, red, etc.)
• Dogs are based on their breeds (German shepherd, Husky, Samoyed, etc.).
• Blood group types (  A, B, AB, O)

Therefore, the correct answer is Blood group type (A, B, AB, O).

The correct answer is Climate Change - Kyoto Protocol.

 

Key Points

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Therefore, the correct answer is Climate Change - Kyoto Protocol.

The correct answer is Leadership in Energy and Environment Design.  

 

Key Points

• LEED (Leadership in Energy and Environmental Design) is an ecology-oriented building certification program run under the auspices of the U.S. Green Building Council (USGBC).
• LEED concentrates its efforts on improving performance across five key areas of environmental and human health: energy efficiency, indoor environmental quality, materials selection, sustainable site development and water savings.
• LEED has special rating systems that apply to all kinds of structures, including schools, retail and healthcare facilities.
• Rating systems are available for new construction and major renovations as well as existing buildings.

Therefore, the correct answer is Leadership in Energy and Environment Design.

The correct answer is A change occurring at a steady rate where the rate is defined by the directions of change.

 

Key Points

• Hysteresis is observed following a perturbation to an equilibrium point when the return trajectory to the original equilibrium point or state is different from the outgoing trajectory.
• In ecological terms, this often means that the work that must be done to return to an original state after a disturbance is much more than the work done by the original perturbation itself.
• Hysteresis is a characteristic of alternative stable states.
• It can be used to identify their presence because it means that more than one state can be observed under identical environmental conditions — at least over some range of conditions.
• Here the perturbation occurs at a steady rate and that rate is dependent on the direction of change i.e., either positive or negative.

Therefore, the correct answer is a change occurring at a steady rate where the rate is defined by the directions of change.

The correct answer is Wagai M. Matthai.

 

Key Points

• Wangari Maathai (1940-2011) was the founder of the Green Belt Movement and the 2004 Nobel Peace Prize Laureate.
• Wangari Maathai was awarded the Nobel Peace Prize in 2004.
• In its citation, the Norwegian Nobel Committee noted Professor Maathai’s contribution to “sustainable development, democracy and peace.”
• The Committee further stated that Professor Maathai “stands at the front of the fight to promote ecologically viable social, economic and cultural development in Kenya and Africa.
• She has taken a holistic approach to sustainable development that embraces democracy, human rights and women’s rights in particular.

​Therefore, the correct answer is Wagai M. Matthai.

The correct answer is Swachh Bharat Abhiyan.

 

Key Points

• Prerak Dauur Samman has been announced as part of Swachh Survekshan 2021.
• The Prerak Dauur Samman has a total of five additional sub-categories -Divya (Platinum), Anupam (Gold), Ujjwal (Silver), Udit (Bronze), and Aarohi (Aspiring) - with the top three cities being recognized in each.
• Swachh Survekshan was launched as a part of the Swachh Bharat Mission, it is an annual survey of cleanliness, hygiene and sanitation in cities and towns across India.

Therefore, the correct answer is Swachh Bharat Abhiyan.

The correct answer is Restriction endonucleases purified from bacteria can be used in vitro. 

 

Key Points

• Recombinant DNA is used to make changes to the original genome of a plant or animal to add desired traits that are not present in them naturally and to delete genes that are harmful to plants and animals.
• This process is known as genetic engineering.
• The presence of restriction endonuclease, which enables us to alter the original DNA sequence, makes genetic engineering conceivable.
• As restriction enzymes, restriction endonucleases can recognise and cut DNA only at specific locations known as restriction sites.

Therefore, the correct answer is restriction endonucleases purified from bacteria can be used in vitro.

The correct answer is Both A and R are true and R is the correct explanation of A.

 

Key Points

• Active ingredients are the chemicals in a pesticide product that act to control pests.
• Organochlorines are a group of chlorinated compounds widely used as pesticides.
• These chemicals belong to the class of persistent organic pollutants (POPs) with high persistence in the environment.
• Most pesticides have organic chlorine compounds as their active component.

Thus the assertion is true.

• The basic characteristics of organochlorine pesticides are high persistence, low polarity, low aqueous solubility and high lipid solubility.
• Organochlorine pesticides can enter the environment after pesticide applications, polluted wastes discarded into landfills, and discharges from industrial units that synthesize these chemicals.
• They are volatile and stable; some can adhere to the soil and air, thus increasing the chances of high persistence in the environment, and are identified as agents of chronic exposure to animals and humans.
• They are highly toxic to insects and are known for their low toxicity to humans.

Thus the reason is also true and it correctly explains the assertion.

Therefore, the correct answer is both A and R are true and R is the correct explanation of A.

The correct answer is Both A and R are true and R is the correct explanation of A.

 

Key Points

• Large bodies of water such as oceans, seas, and large lakes affect the climate of an area.
• The water heats and cools more slowly than land.

Thus the assertion is true.

• Water is a liquid at room temperature because of the strong hydrogen bond between the molecules of water.
• This means that it takes more energy or heat to increase water’s temperature than it does for most other substances.
• The specific heat of liquid water is 1 calorie per gram per 1 °C (cal/g/°C).
• The specific heat of water is greater than that of dry soil, therefore water both absorbs and releases heat more slowly than land.
• Water also is fluid, allowing the heat to be mixed to a greater depth than on land.
• Oceans have a greater heat capacity than land because the specific heat of water is greater than that of dry soil and because the mixing of the upper ocean results in a much larger mass of water being heated than land.
• This causes land areas to heat more rapidly and to higher temperatures and also cool more rapidly and to lower temperatures, compared to oceans.

Thus the reason is also true and it correctly explains the assertion.

Therefore the correct answer is both A and R are true and R is the correct explanation of A.

The correct answer is Both A and R are true and R is the correct explanation of A.

 

Key Points

• Wind power is one of the indirect solar energy technologies.
• The wind is used to produce electricity by converting the kinetic energy of air in motion into electricity.
• Wind speed largely determines the amount of electricity generated by a turbine.
• Higher wind speeds generate more power because stronger winds allow the blades to rotate faster.
• Faster rotation translates to more mechanical power and more electrical power from the generator.

The wind energy produced is calculated using the equation, 

Energy = 1/2 ρ Av³η 

Where, ρ = density of air

v = velocity of air

A = area of the blade

η = efficiency

• The energy produced from wind is directly proportional to the third power is the wind speed.
• So doubling the wind velocity increases the wind energy by eight times.
• Also, ground-level obstacles such as vegetation, buildings, and topographic features tend to slow the wind near the surface.
• Because the effect of these obstacles decreases with height above ground, wind speeds tend to increase with height above ground.

Therefore, both A and R are true and R is the correct explanation of A.

The correct answer is Both A and R are true and R is the correct explanation of A.

 

Key Points

• Ionizing radiation is a form of energy that acts by removing electrons from atoms and molecules of materials that include air, water, and living tissue.
• These radiations consist of particles (neutrons, beta or alpha), X-rays, or gamma rays with sufficient energy to cause ionization in the medium through which it passes.
• Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus,  beta particles are identified as electrons, and gamma rays as a form of electromagnetic radiation like x-rays, except much higher in energy and even more dangerous to living systems.

​Thus the assertion is true.

• The spontaneous disintegration of atoms is called radioactivity, which liberates alpha and beta particles and the excess energy emitted is a form of ionizing radiation.
• These ionizing radiations are capable of ionizing atoms and molecules of the matter through which they pass

Thus the reason is true and it correctly explains the assertion.

Therefore, the correct answer is both A and R are true and R is the correct explanation of A.

The correct answer is A - IV, B - II, C - III, D - I.

Key Points

 

 

 

 

 

Therefore, the correct answer is A - IV, B - II, C - III, and D - I.

Additional Information

• The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases.
• Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period, relative to the emissions of 1 ton of carbon dioxide (CO₂).
• The larger the GWP, the more that a given gas warms the Earth compared to CO₂ over that period.
• CO₂, by definition, has a GWP of 1 regardless of the period used, because it is the gas being used as the reference.
• Methane (CH₄) is estimated to have a GWP of 27-30 over 100 years.
• Nitrous Oxide (N₂O) has a GWP 273 times that of CO₂ for a 100-year timescale.
• Chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆) are sometimes called high-GWP gases because, for a given amount of mass, they trap substantially more heat than CO_2.

The correct answer is A - III, B - IV, C - II, and D - I.  

Key Points

 

 

 

 

 

Therefore, the correct answer is A - III, B - IV, C - II, and D - I.  

Additional Information

• Above Ground Landfill (Area Landfill): The area landfill is used when the terrain is unsuitable for the excavation of trenches in which to place the solid waste. High-groundwater conditions necessitate the use of area-type landfills. Site preparation includes the installation of a liner and leachate control system. Cover material must be hauled in by truck or earthmoving equipment from adjacent land or b-pit areas.
• Below Ground Landfill (Trench Landfill): The trench method of landfilling is ideally suited to areas where an adequate depth of cover material is available at the site and where the water table is not near the surface. Typically, solid wastes are placed in trenches excavated in the soil. The soil excavated from the site is used for the daily and final cover. The excavated trenches are lined with low-permeability liners to limit the movement of both landfill gases and leachate. Trenches vary from 100 to 300 m in length, 1 to 3 m in depth, and 5 to 15 m in width with side slopes of 2:1.
• Slope Landfill: In hilly regions, it is usually not possible to find flat ground for landfilling. Slope landfills and valley landfills have to be adopted. In a slope landfill, waste is placed along the sides of the existing hill slope. Control of inflowing water from hillside slopes is a critical factor in the design of such landfills.
• Valley Landfill: Depressions, low-lying areas, valleys, canyons, ravines, dry borrow pits etc. have been used for landfills. The techniques to place and compact solid wastes in such landfills vary with the geometry of the site, the characteristics of the available cover material, the hydrology and geology of the site, the type of leachate and gas control facilities to be used, and the access to the site. Control of surface drainage is often a critical factor in the development of canyon/depression sites.

The correct answer is A-II, B - III, C - I, and D - IV.

Key Points

 

 

 

 

 

 

 

Therefore, the correct answer is A-II, B - III, C - I, and D - IV.

Additional Information 

• A standard deviation (or σ) is a measure of how dispersed the data is about the mean. A low standard deviation means data are clustered around the mean, and a high standard deviation indicates data are more spread out. Therefore, its a measure of variability in a sample.
• The standard error is used to estimate the efficiency, accuracy, and consistency of a sample. In other words, it measures how precisely a sampling distribution represents a population. For a large sample, a 95% confidence interval is obtained as the values 1.96 × SE on either side of the mean.
• Regression analysis is a powerful statistical method that allows you to examine the relationship between two or more variables of interest (dependent and independent variables).
• Bonferroni was used in a variety of circumstances, most commonly to correct the experiment-wise error rate when using multiple t-tests or as a post-hoc procedure to correct the family-wise error rate following analysis of variance (ANOVA).​

The correct answer is A - III, B - I, C - IV, D - II.

Key Points

 

 

 

 

Therefore, the correct answer is A - III, B - I, C - IV, and D - II.

 Additional Information

• A geologic hazard or geohazard is an adverse geologic condition capable of causing widespread damage or loss of property and life.
• Geohazards can be relatively small features, but they can also attain huge dimensions (e.g., submarine or surface landslide) and affect local and regional socio-economics to a large extent (e.g., tsunamis).
• Chemical hazards and toxic substances pose a wide range of health hazards (such as irritation, sensitization, and carcinogenicity) and physical hazards (such as flammability, corrosion, and explosibility).
• Hydrometeorological hazards—including floods, droughts, landslides, and storm surges—threaten lives and impact livelihoods.
• Biological health hazards include bacteria, viruses, parasites and moulds or fungi. They can pose a threat to human health when they are inhaled, eaten or come in contact with skin.

The correct answer is A - III, B - IV, C - II, and D - I.  

Key Points

 

 

 

 

Therefore, the correct answer is A - III, B - IV, C - II, and D - I. 

 Additional Information

• The Pong Dam, also known as the Beas Dam, is an earth-fill embankment dam on the Beas River in the state of Himachal Pradesh, India, just upstream of Talwara. The purpose of the dam is water storage for irrigation and hydroelectric power generation.
• Harike is one of the largest man-made wetlands of northern India which shares its area with the Tarntaran, Ferozpur and Kapurthala districts of Punjab.
• Kolleru Lake is one of the largest freshwater lakes in India located in the state of Andhra Pradesh and forms the largest shallow freshwater lake in Asia (with 245 km2 of the lake area and 302 km2 of total Ramsar designated wetland).
• Point Calimere Wildlife & Bird Sanctuary is the only site in Tamil Nadu to be declared as a Ramsar Site on 19^th August 2002 and has been designated as Ramsar Site No. 1210.

The correct answer is Acidic.

 

Key PointsConsider the tird sentence of the first paragraph of the passage: Even in the pristine environment rain is slightly acidic (5.6 pH) in comparison to neutral pH of 7 for water because of the presence of natural CO2 in the atmosphere. 

• Thus we can conclude that in the pristine environment, the pH of rainwater is slightly acidic (5.6 pH).

Therefore, the correct answer is acidic.

The correct answer is H2SO4 > HNO3.

 

Key PointsExamine the fourth sentence of the first paragraph of the passage: Acid-forming precursor gases, e.g., SO2 and NOx further lower the pH of rainwater and such rainwater having a pH less than 5.6 (pH of natural rainwater) is termed acidic rain.

Examine the fifth sentence of the passage: However nitrogen oxide species before combining with water droplets to form nitric acid undergo photodissociation.

• Thus we can conclude that acid rain contains a mixture of  H2SO4 and HNO3 which lower the pH of rainwater. Since NOx undergoes photodissociation before forming the HNO3, therefore, acid rain contains more H2SO4 than HNO3.

Therefore, the correct answer is H2SO4 > HNO3.

The correct answer is an increase in soil fertility.

 

Key PointsLook at the second sentence of the third paragraph of the passage: Acidic rainwater reduces the cation exchange capacity of the soil and hence crop productivity of the soil.

• Thus we can conclude that acid rain causes a decrease in soil fertility by decreasing its cation exchange capacity and lowering its buffering capacity.

Therefore, the correct answer is an increase in soil fertility.

The correct answer is SO2.

 

Key PointsLook at the fourth and fifth sentences of the passage:

Fourth sentence: Acid-forming precursor gases, e.g., SO2 and NOx further lower the pH of rainwater and such rainwater having a pH less than 5.6 (pH of natural rainwater) is termed acidic rain.

Fifth sentence: However nitrogen oxide species before combining with water droplets to form nitric acid undergo photodissociation.

• Thus we can say that acid rain predominantly contains  SO2 because NOx undergoes photodissociation before forming nitric acid.

Therefore, the correct answer is SO2.

The correct answer is the Presence of carbonate-rich particles.  

 

Key PointsConsider the second sentence of the last paragraph of the passage: This is because of carbonate-rich dust present in the atmosphere.

• Thus we can conclude that the cases of acidic rain are very limited in northern India irrespective of high SO2 and NOx emissions because of carbonate-rich dust present in the atmosphere.

Therefore, the correct answer is the presence of carbonate-rich particles.

The correct answer is ~104.7 μg/m3.

Key Points Given: 

Concentration of SO₂ = 40 ppb

Temperature = 25°C

The molecular weight of SO2 = 64

Using the formula: $\mu g/m^3 = {Conc.\ in\ ppb\ \times\ Mol. weight \over 24.45}$

$\mu g/m^3 = {40\ \times\ 64 \over 24.45}$ = ~104.7 μg/m3

Therefore, the correct answer is ~104.7 μg/m3.

The correct answer is Indicator (Chemical/Chemical class), Averaging time, Pollutant form and level.

 

Key Points

• The National Ambient air quality standards (NAAQs) set by the CPCB apply to the whole country.
• The pollutants that are covered under the National Ambient Air Quality Standards include:

1. Sulphur dioxide (SO₂),
2. Nitrogen dioxide (NO₂),
3. The particulate matter having a size of fewer than 10 microns (PM₁₀),
4. The particulate matter having a size less than 2.5 microns (PM_2.5),
5. Ozone
6. Lead
7. Carbon monoxide (CO)
8. Arsenic
9. Nickel
10. Benzene
11. Ammonia, and
12. Benzopyrene

• The NAAQs include the chemical/pollutant name and form, average time weighted (1 hour, 8 hours, 24 hours and annual) and concentration in ambient air (in industrial, residential and rural areas and ecologically sensitive areas).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Therefore, the correct answer is Indicator (Chemical/Chemical class), Averaging time, Pollutant form and level.

The correct answer is Invasion.

 

Key Points

• Primary succession starts from the primitive substratum where there was no previously any sort of living matter.
• The first group of organisms established there are known as the pioneers or primary colonisers.
• The general process of primary succession includes:
• Nudation
• Invasion (migration, ecesis, aggregation)
• Competition and coaction
• Reaction, and
• Stabilisation (Climax)
• Secondary succession starts from a previously built-up substratum with already existing living matter.
• The action of any external force, such as a sudden change in climatic factors, biotic intervention, fire etc., causes the existing community to disappear.
• Thus the area becomes devoid of living matter but its substratum, instead of primitive, is built-up.
• Such successions are comparatively more rapid and species do not need to invade a new habitat for their growth.

Therefore, the correct answer is an invasion.

The correct answer is MacArthur and Wilson (1967).

 

Key Points

• The r and k classification was originally proposed by the biologists Robert MacArthur and E.O. Wilson (1967).
• The r-selected species live in highly variable populations.
• The fittest individuals in these environments have many offsprings and reproduce early.
• Examples: Oysters, insects, daphnia, goldenrod etc.
• K-selected species live in populations that are at or near equilibrium conditions for long periods.
• Competition for limited resources is very important in these environments.
• Examples: Lemurs, bats, elephants, giraffes etc.

Therefore, the correct answer is MacArthur and Wilson (1967).

The correct answer is comparing the relative degree of tolerance of an organism to a given environmental factor.

 

Key Points

• The prefix "steno" and "eury" have been used for comparing the relatively narrow and wide degree of tolerance, respectively of an organism to a given environmental factor.
• Examples:
• Stenohydric and euryhydric refer to narrow and wide tolerance respectively to water.
• Stenohaline and euryhaline refer to narrow and wide tolerance respectively to salinity.
• Stenophagic and euryphagic refer to narrow and wide tolerance respectively to food.
• Stenoecious and euryoecious refer to narrow and wide tolerance respectively to habitat selection.
• Stenothermal and eurythermal refer to narrow and wide tolerance respectively to temperature.

Therefore, the correct answer is comparing the relative degree of tolerance of an organism to a given environmental factor.

The correct answer is Jet streams.

 

Key Points

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Therefore, the correct answer is jet streams.

The correct answer is recharge and Discharge in a freshwater aquifer.

 

Key Points

• Near coastlines, the subsurface seawater-groundwater interface creates a boundary to fresh groundwater flow.
• The boundary acts as a physical boundary that limits flow, forcing fresh unconfined groundwater to discharge along the coastline.
• The interface behaves as a Type 2 no-flow boundary.
• The boundary is not a sharp interface because its position shifts with the tidal cycles and as freshwater discharge rates vary.
• A mixing zone between freshwater and seawater occurs and is referred to as the transition zone.
• In its simplest form, it can be assumed the boundary acts as an impermeable physical boundary.
• This boundary is determined by the amount of water that enters and leaves the freshwater aquifer i.e., its recharge and discharge.
• The boundary forces freshwater groundwater to discharge along the coastline.

Therefore, the correct answer is recharge and Discharge in a freshwater aquifer.

The correct answer is global solar radiation.

 

Key Points

• Every location on earth receives sunlight for at least part of the year.
• As sunlight passes through the atmosphere, some of it is absorbed, scattered, and reflected by air molecules, water vapour, clouds, dust etc. This is called diffuse solar radiation.
• The solar radiation that reaches the earth's surface without being diffused is called direct beam solar radiation.
• The sum of diffuse and direct solar radiation is called global solar radiation.
• Atmospheric conditions can reduce direct beam radiation by 10% on clear, dry days and by 100% during thick, cloudy days.
• Global radiation (G) = I × sin (h) + D
• Where, direct radiation (I) = The direct radiation from the sun towards a surface perpendicular to the sun
• h = the sun's height
• Diffuse radiation (D) = The radiation that reaches a horizontal surface and does not come directly from the sun

The correct answer is Silicon.

 

Key Points

• Solar cells are devices that convert the sun's radiation energy into electricity.
• Solar cells contain a semiconductor.
• Silicon is a good semiconductor that can be used for the production of solar cells.
• Silicon is, by far, the most common semiconductor material used in solar cells, representing approximately 95% of the modules sold today.
• It is also the second most abundant material on earth (after oxygen) and the most common semiconductor used in computer chips.
• Crystalline silicon cells are made of silicon atoms connected to form a crystal lattice.
• This lattice provides an organized structure that makes the conversion of light into electricity more efficient.
• Solar cells made out of silicon currently provide a combination of high efficiency, low cost, and long lifetime.
• Modules are expected to last for 25 years or more, still producing more than 80% of their original power after this time.

Therefore, the correct answer is Silicon.

The correct answer is A, B and E only.

Key Points

• Basalts are common aphanitic igneous extrusive (volcanic) rocks.
• Basalts are composed of minute grains of plagioclase feldspar (generally labradorite), pyroxene, olivine, biotite, hornblende and <20% quartz.
• Nepheline or leucite may associate or proxy the feldspar giving rise to verities with special names.
• The ferromagnesian minerals are mainly amphibole and rarely biotite.
• Basalts are usually dark grey to black.

Therefore, the correct answer is A, B and E only.

The correct answer is C, B, D, E, and A.

Key Points

• The Goldich dissolution series is a method of predicting the relative stability or weathering rate of common igneous minerals on the Earth's surface, with minerals that form at higher temperatures and pressures less stable on the surface than minerals that form at lower temperatures and pressures.
• The Goldich dissolution series concerns intrinsic mineral qualities, which were proven both by Goldich as well as preceding scientists to also be important for constraining weathering rates.
• According to the series, the increasing order of stability for weathering is:
• ​Calcite, Olivine, Ca rich feldspar, Na rich feldspar and Illite.

Therefore, the correct answer is C, B, D, E, and A.

The correct answer is A, B, C, and D.

Key Points

• Traditionally, membranes have been classified as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, based roughly on the minimum size of the contaminant that is excluded from passing through the particular membrane.
• As the size of the contaminant excluded becomes smaller, the membrane is said to become tighter.

​

 

 

 

 

 

 

 

 

 

 

 

 

• The order of increase in the membrane size is microfiltration, ultrafiltration, nano-filtration and reverse osmosis.

Therefore, the correct answer is A, B, C, and D.

The correct answer is Statement I is true but Statement II is false. 

Key Points

• Ecotypes are discrete entities with clear differences which separate one ecotype from another.
• The differences are not due to the plastic response to changes in the environment but are the natural selection of locally adapted populations.
• The term ecotype was proposed by Turesson (1922) to the groupings of populations or ecological races or sub-species of a species about different environmental or habitat conditions.
• These are inter-fertile forms or biotypes of a species which possess different genetic compositions or genotypes and arise due to mutations, hybridization and isolation.

Thus the statement I is true.

• Ecotype is the product of the genetic response of a population to a habitat.
• In ecotypes adaptations are irreversible, i.e., they retain their features even when planted in a neutral habitat.

Thus statement II is false.

Therefore, the correct answer is that statement I is true but statement II is false.

The correct answer is Both Statements I and Statement II are true.  

Key Points

• A confined aquifer is an aquifer confined between two impermeable beds such as aquifuge, aquiclude, etc.
• The water in the confined aquifer will be under greater pressure which is greater than atmospheric pressure.
• Hence, the water level shown by the piezometer is always higher than the top level of the confined aquifer.

Thus the statement I is true.

• Confined aquifers are generally recharged where the aquifer materials are exposed at the surface (outcrop).
• Properly identifying the recharge area is critical in groundwater protection because the introduction of contaminants within the recharge area can cause aquifer contamination.

Thus statement II is true.

Therefore, the correct answer is both statements I and statement II are true.

The correct answer is Both Statements I and Statement II are true.  

Key Points

• All noise is caused by vibrations in the air that are picked up by tiny hairs in our ear canal, which then travel to our inner ear.
• Typically, the louder the sound, the larger the vibration.
• Precise measurement and scientific description of sound levels differ from most subjective human perceptions and opinions about sound.
• Subjective human responses to noise depend on both pitch and loudness.
• People with normal hearing generally perceive high-frequency sounds to be louder than low-frequency sounds of the same amplitude.
• In contrast, air pollutants similarly affect humans with children, older people, and sensitive people more prone to it.

​Thus the statement I is true.

• Noise pollution is defined as any unwanted sound which is irrespective of its loudness.
• Noise pollution adversely affects the lives of millions of people.
• Studies have shown that there are direct links between noise and health.
• Problems related to noise include stress-related illnesses, high blood pressure, speech interference, hearing loss, sleep disruption, and lost productivity.

Thus statement II is true.

Therefore, the correct answer is both statements I and statement II are true.

The correct answer is Statement I is true but Statement II is false.  

Key Points

 

• A baghouse filter is an air pollution control device that removes particulates of air or gas released from commercial processes or combustion for electricity generation.
• The gas is drawn through the bags, either on the inside or the outside depending on the cleaning method, and a layer of dust accumulates on the filter media surface.
• Functioning baghouses typically have a particulate collection efficiency of 99% or better, even when particle size is very small.
• Baghouses operate most effectively within a certain pressure drop range.

Thus the statement I is true.

• Dust cake continues to build until the thickness reaches a level where flow is sufficiently restricted; at this point, the bags are cleaned.
• When sufficient pressure drop occurs, the cleaning process begins.
• This spectrum is based on a specific gas volumetric flow rate.
• When dust accumulates, pressure drop decreases and hence efficiency decreases.

Thus statement II is false.

Therefore, the correct answer is that statement I is true but statement II is false.

The correct answer is A, B, C and D only.

Key Points

• A population is defined as a group of individuals of the same species living and interbreeding within a given area.
• Members of a population often rely on the same resources, are subject to similar environmental constraints, and depend on the availability of other members to persist over time.
• Some of the most important characteristics of the population are as follows: 
• population size,
• density,
• age structure,
• natality (birth rates),
• mortality (death rates), and
• sex ratio

Therefore, the correct answer is A, B, C and D only.

The correct answer is B and D only.  

Key Points

• The mantle makes up 84% of the Earth by volume, compared to 15% in the core and the remainder is taken up by the crust.
• While it is predominantly solid, it behaves like a viscous fluid because temperatures are close to the melting point in this layer.
• The mantle is divided into sections which are based on results from seismology.
• These are the upper mantle, which extends from about 7 to 35 km (4.3 to 21.7 mi) from the surface down to a depth of 410 km (250 mi); the transition zone, which extends from 410 to 660 km (250 – 410 mi); the lower mantle, which reaches from 660 km to a depth of 2,891 km (410 – 1,796 mi); and the core-mantle boundary, which has a variable thickness (~200 km or 120 mi on average).
• In terms of its constituent elements, the mantle is made up of 44.8% oxygen, 21.5% silicon, and 22.8% magnesium.
• There’s also iron, aluminium, calcium, sodium, and potassium.
• These elements are all bound together in the form of silicate rocks, all of which take the form of oxides.
• The most common is Silicon dioxide (SiO₂) at 48%, followed by Magnesium Oxide (MgO) at 37.8%.

Therefore, the correct answer is B and D only.

The correct answer is C only.

Key Points

Solar energy offers considerable advantages: 

• Solar power is low-emission.
• Solar panels produce no pollution, although they impose environmental costs through manufacture and construction.
• These environmental tolls are negligible, however, when compared with the damage inflicted by conventional energy sources
• Although solar energy can still be collected during cloudy and rainy days, the efficiency of the solar system drops.
• Solar panels are dependent on sunlight to effectively gather solar energy.
• Therefore it is intermittent in its availability.
• Solar energy has to be used right away, or it can be stored in large batteries.
• These batteries, used in off-the-grid solar systems, can be charged during the day so that the energy is used at night.
• Solar energy systems generally don’t require a lot of maintenance.
• Also, as there are no moving parts, there is no wear and tear.
• Therefore, operating costs are low.
• When measured solar energy has a density of 1.5 micro Joules per cubic meter, over twenty quadrillion times less than oil.​

Therefore, the correct answer is C only.

The correct answer is B and D only.  

Key Points

• The p-value is used in the context of null hypothesis testing to quantify the statistical significance of a result, the result being the observed value of the chosen statistic.
• The lower the p-value is, the lower the probability of getting that result if the null hypothesis were true.
• A result is said to be statistically significant if it allows us to reject the null hypothesis.
• The chance that one commits type-I errors is known as the type-I error rate or significance level (p-value) this number is conventionally and arbitrarily set to 0.05 (5%).
• In simple words, the p-value is the probability of type-1 error computed after data analysis is done
• If the p-value is below your threshold of significance (typically p < 0.05), then you can reject the null hypothesis, but this does not necessarily mean that your alternative hypothesis is true.

Therefore, the correct answer is B and D only.

The correct answer is B and D only.

Key Points

• Parametric tests evaluate hypotheses for a particular parameter usually the population mean and are employed in quantitative data analysis.
• The data should have a normal distribution.
• Examples of parametric tests include:
• Student t-test
• F test
• Z test
• Non-parametric tests are used to evaluate hypotheses for entire population distributions and are employed for qualitative data analysis.
• It requires no assumptions for the data to have a normal distribution.
• Examples of non-parametric tests include:
• Mann-Whitney-Wilcoxon (MWW) test.
• The Wilcoxon test.
• χ² test

Therefore, the correct answer is B and D only.

The correct answer is C and D only.  

Key Points

 

 

 

 

 

 

 

• The probability that an observation under the normal curve lies within 1 standard deviation of the mean is approximately 0.68.
• The probability that an observation under the normal curve lies within 2 standard deviations of the mean is approximately 0.95.
• The probability that an observation under the normal curve lies within 3 standard deviations of the mean is approximately 0.99.

 Properties of a normal curve:

• The values of mean, median, and mode in a normal curve are located on the same point.
• It is a symmetric curve centred around the mean, whereas 50% of the observation lies on the right side of the mean and 50% of the observations lie on the left side of the mean.
• It is a bell-shaped and unimodal curve.

Therefore, the correct answer is C and D only.

The correct answer is A - IV, B - III, C - II, D - I.

Key Points

 

 

 

 

Additional Information

• Monoclimax Theory and Clements:
• Clements’ model focuses on the climatic climax as a singular endpoint for all successions in a given climate zone.
• It simplifies ecological succession to a predictable and uniform process driven predominantly by climate.
• Polyclimax Theory and Tansley:
• Tansley’s theory acknowledges multiple factors influencing climax communities, making it more flexible than the Monoclimax Theory.
• This theory highlights the heterogeneity of landscapes and the variability in ecological outcomes.
• Climax-pattern Theory and Whittaker:
• Whittaker’s approach integrates the concepts of both single and multiple climax theories.
• It recognizes the gradient nature of ecological influences and the resultant diversity of climax communities.
• Cyclic Climax Theory and Watt:
• Watt’s model introduces the idea of cyclic succession, where climax communities may repeat in cycles due to disturbances.
• This approach accounts for dynamic and non-linear processes in ecological succession.

The correct answer is A-II, B - I, C - III, and D - IV.

Key Points 

 

 

 

 

Therefore, the correct answer is A-II, B - I, C - III, and D - IV.

Additional Information

• Arsenates are salts or esters of arsenic acid.
• Arsenates occur naturally in a variety of minerals.
• Red lead is a mixed lead oxide containing Pb²⁺ and Pb⁴⁺ lead ions with an overall formula of Pb₃O₄.
• The pigment has been artificially prepared since antiquity but can also be found in nature as the mineral minimum.
• White lead is a complex salt, containing both carbonate and hydroxide ions.
• White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of cerussite.
• Sodium arsenite is used in the water gas shift reaction to remove carbon dioxide.

The correct answer is Mass.

 

Key Points

• The continuity equation is an expression representing the idea that matter is conserved in a flow.
• Per unit volume, the sum of all masses flowing in and out per unit of time must be equal to the change of mass due to a change in density per unit of time.
• The continuity equation applies to all kinds of flows, including compressible, incompressible, Newtonian, and non-Newtonian flows.
• This can be expressed in the form of an equation:
• \(m_{in}\ - m_{out} = {∂\over ∂t}m{element}\)

Therefore, the correct answer is mass.

The correct answer is the dose that affects 50% of the population or observed subjects.

 

Key Points

• The ED-50 is the dose required to achieve 50% of the desired response in 50% of the population.
• It is thus calculated from a dose-response curve by dropping a line on the dose axis where 50% of the desired response is seen.
• The ED-50 of any toxicant varies depending on the effect measured.
• In general, the less severe the effect measured, the lower the ED-50 for that particular effect.
• Toxicants are not tested in humans in such a fashion.
• Instead, animals are used to predict the toxicity that may occur in humans.

​Therefore, the correct answer is the dose that affects 50% of the population or observed subjects.

The correct answer is the Diversity-stability hypothesis.  

 

Key Points

Diversity-stability hypothesis:

• The diversity-stability hypothesis states that the more diverse a community is, the more stable and productive the community is.
• This hypothesis was formed on the basis that more stable and productive communities can use their resources better and more efficiently as compared to communities of less diversity.
• There are correlations with stability measures like the constancy of community production and community resilience to species loss and also alterations to the relative abundance of different species.
• The statement that can be used to support the hypothesis is that tropical rainforests (which are more diverse) have fewer pest outbreaks than temperate forests.

Therefore, the correct answer is the Diversity-stability hypothesis.  

 

Additional InformationRivet-popper hypothesis:

• The rivet-popper hypothesis was proposed by Paul Ehrlich.
• The hypothesis suggests the importance of species richness in the maintenance of the ecosystem.

Redundancy hypothesis:

• The redundancy hypothesis predicts that species redundancy in a plant community enhances community stability.

Idiosyncratic hypothesis:

• The idiosyncratic hypothesis suggests that changing the number of species influences ecosystem processes, but no obvious pattern is evident; hence, the role of biodiversity is unpredictable.

The correct answer is the influence of Earth's rotations, which tends to turn air towards the right in the Northern Hemisphere.

 

Key Points

• The Coriolis effect is an apparent deflection of the path of an object that moves within a rotating coordinate system.
• The object does not deviate from its path, but it appears to do so because of the motion of the coordinate system.
• The Coriolis effect is most apparent in the path of an object moving longitudinally.
• On earth, an object that moves along a north-south path, or longitudinal line, will undergo apparent deflection to the right in the Northern Hemisphere and the left in the Southern Hemisphere.
• There are two reasons for this phenomenon: first, the earth rotates eastward; and second, the tangential velocity of a point on earth is a function of latitude (the velocity is essentially zero at the poles and it attains a maximum value at the Equator).
• Thus, if a cannon were fired northward from a point on the Equator, the projectile would land to the east of its due north path.
• The Coriolis deflection is therefore related to the motion of the object, the motion of Earth, and the latitude.

Therefore, the correct answer is the influence of Earth's rotations, which tends to turn air towards the right in the Northern Hemisphere.

The correct answer is Both A and R are true and R is the correct explanation of A.

 

Key Points

• Dematerialization is the progressive decrease in a product's size and weight due to technological improvements.
• It is part of the source reduction process in waste management.

Thus the assertion is true.

• Technological improvements lead to the creation of new products which are less in size, more energy efficient, more reliable and more durable.
• The new products are better designed to suit modern demands and are more environmentally friendly.

Thus the reason is also true and it correctly explains the assertion.

Therefore, the correct answer is both A and R are true and R is the correct explanation of A.

The correct answer is A, B, E, D, and C.

Key Points

• In the case of the interpretation of satellite images, the characteristics of objects are studied regarding single or multiple spectral bands because there is generally more than one image acquired in different spectral regions of the electromagnetic spectrum.
• Image interpretations employ a combination of the following elements:

1. Location
2. Tone
3. Size
4. Shape
5. Texture
6. Association
7. Shadow
8. Site, and
9. Pattern.
10. Situation

• The elements in the order of their complexity are Location, Tone, Texture, Pattern and Situation.

Therefore, the correct answer is A, B, E, D, and C.

Additional Information

The correct answer is Statement I is false but Statement II is true.

Key Points

• Carotenoids are a key group of pigments that absorb violet and blue-green light.
• The carotenoid pigment is present in thylakoids and absorbs light violet and blue and reflects longer wavelengths i.e., yellow, red and orange light.
• Xanthophyll is a type of pigment that is colour.
• It absorbs violet and blue-green colour and reflects (does not absorb) yellow colour with a wavelength of 560-585nm.

Thus the statement I is false.

• The palisade mesophyll layer is made up of closely-packed, elongated cells located just below the upper epidermis.
• They contain chloroplasts and carry out most of the photosynthesis.
• Accessory pigments are light-absorbing molecules that function in tandem with chlorophyll and photosynthetic organisms.
• These accessory pigments include carotenoids, xanthophylls, anthocyanin etc.

Thus statement II is true.

Therefore, the correct answer is that statement I is false but statement II is true.

The correct answer is A, B, C and D.

Key Points

• The biochemical oxygen demand (BOD) is a crucial environmental index for determining the relative oxygen requirements of wastewater, effluents, and polluted water.
• It refers to the quantity of oxygen required by bacteria and other microorganisms in the biochemical degradation and transformation of organic matter under aerobic conditions.
• The BOD is also interpreted as a measure of the concentration of organic material that can serve as a substrate to support the growth of microorganisms.
• The BOD test, as used for assessing the efficiency of wastewater treatment, is intended to measure some fraction of the carbonaceous oxygen demand, i.e., the oxygen consumed by heterotrophic microorganisms that utilize the organic matter of the waste in their metabolism, and not the oxygen demand exerted by autotrophic nitrifying bacteria.
• The BOD test measures the strength of the wastewater by measuring the amount of oxygen used by the bacteria as they stabilize the organic matter under controlled conditions of time and temperature.
• Biochemical oxygen demand is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have on the receiving environment.

Therefore, the correct answer is A, B, C and D.

The correct answer is B, D and E only. 

Key Points

• The low waste approach is a holistic set of principles focused on waste prevention that encourage redesigning resource life cycles so that all products are repurposed and/or reused.
• The goal is to avoid sending trash to landfills, incinerators, the ocean, or any other part of the environment. I.e., the focus is not on waste management but on reducing it from the source.
• It relies on a circular economy.
• The concept of the circular economy aims to keep raw materials in a closed loop.
• In this way, resources are maximally used, the need for new ones is reduced, waste is avoided and the life cycle of products is increased.

​Therefore, the correct answer is  B, D and E only.

The correct answer is A, B, C and E only.  

Key Points

• Solid waste is defined as any discarded material that is abandoned by being disposed of, burned or incinerated, recycled or considered waste-like.
• Sludge and slurry are by-products of industrial, refining or wastewater treatment processes.
• Sludge is a thick, soft, wet mixture of liquid and solid components.
• A slurry is a thin, sloppy, wet mixture of liquid and solid components.
• Combustible waste means all waste substances capable of incineration or burning, but excluding explosive or highly inflammable material.
• Wastewater is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes.
• All of these wastes are subdivided based on their physical properties viz their physical state(solid, liquid or gas), density etc.
• Reactive wastes are categorised based on their chemical property to interact with matter.
• Reactive Wastes are wastes that readily explode or undergo violent reactions.
• A waste is considered reactive if it explodes or reacts violently when exposed to water or under normal handling conditions, creating toxic fumes or gases when exposed to water or under common handling conditions.

Therefore, the correct answer is  A, B, C and E only.

Explanation:

• The United States Department of Agriculture is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food.
• The classification of the soil particles according to this system is as follows,

 

Hence, option 4 is the correct answer.

The correct answer is ~71.4 mg/l.

 

Key PointsGiven: 

Volume of wastewater = 21 ml

The volume of wastewater plus dilution water = 300 ml

DO₁ = 10 mg/l

DO₅ = 5 mg/l

Using the formula: $BOD_5 = {DO_i \ - DO_f\over P}$

$P = {Volume\ of\ wastewater\over Volume\ of\ wasterwater\ plus\ dilution\ water}$

$P = {21\over 300}$ = 0.07

$BOD_5 = {10 \ -\ 5\over 0.07}$ = ~71.4 mg/l

Therefore, the correct answer is ~71.4 mg/l.

Explanation:

Primary Pollutants and Secondary Pollutants:

• Primary pollutants are substances that are directly emitted into the atmosphere from sources.
• Primary pollutants are those that are emitted directly from identifiable sources.
• Secondary air pollutants are those that are produced in the air by the interaction of two or more primary air pollutants.

Additional Information

Primary Air pollutants: 

(i) Fine (less than 100μ) and coarse (more than 100μ) suspended particulate matter

(ii) Oxides of sulfur

(iii) Oxides of nitrogen

(iv) Carbon monoxide

(v) Halogens

(vi) Organic compounds

(vii) Radioactive compounds

Secondary Air pollutants:

(i) Ozone

(ii) PAN (peroxi aceyl nitrate)

(iii) Photochemical smog

(iv) Acid mists

The correct answer is Both A and R are true and R is the correct explanation of A.

 

Key Points

• Cool pavements include a range of established and emerging technologies that communities are exploring as part of their heat island reduction efforts.
• Cool pavement technologies utilize various strategies to reduce the temperature of new and existing pavements, including increased albedo, evaporative cooling, and reduced heat conduction.
• The properties and principles of cool pavements include reflectivity due to light colour, thermal emittance, heat transfer, thermal capacity, and permeability.

Thus the assertion is true.

• Research shows that building lighter-coloured, more reflective roads have the potential to lower air temperatures by more than 2.5 degrees Fahrenheit (1.4 C) and, in the process, reduce the frequency of heat waves by 41%.
• Permeable pavements allow water to permeate typically impermeable surfaces and evaporate when the material’s temperature rises.
• Permeable pavements are more suited to hot and humid conditions, as rainfall is primarily used to cool the pavement’s surface.
• Wastewater can also be used as a source of evaporation.

Thus the reason is also true and it correctly explains the assertion.

Therefore, the correct answer is both A and R are true and R is the correct explanation of A.

The correct answer is E, C, A, B, and D.

Key Points

• The waste management hierarchy presents a systematic order of managing waste according to what’s best for the environment.
• It is a conceptual framework designed to guide and rank waste management decisions at both the individual and organisational levels.
• It gives top priority to waste prevention, followed by reuse, recycling, recovery and finally disposal.
• The waste hierarchy is:
• Avoidance includes action to reduce the amount of waste generated by households, industry and all levels of government.
• ​Resource recovery including reuse, recycling, reprocessing and energy recovery, is consistent with the most efficient use of the recovered resources. It includes waste treatment, waste separation and waste concentration.
• Disposal includes management of all disposal options in the most environmentally responsible manner like the use of landfills.

Therefore, the correct answer is E, C, A, B, and D.

The correct answer is Both Statements I and Statement II are true.  

Key Points

• At an MSW combustion facility, MSW is unloaded from collection trucks and placed in a trash storage bunker.
• An overhead crane sorts the waste and then lifts it into a combustion chamber to be burned.
• The heat released from burning converts water to steam, which is then sent to a turbine generator to produce electricity.
• The remaining ash is collected and taken to a landfill where a high-efficiency baghouse filtering system captures particulates.
• In comparison to this, highly toxic and hazardous wastes are destroyed by hazardous waste combustion techniques like incinerators.
• It is the chemical process which includes the reaction between hazardous substances and oxygen, which produces energy as a by-product, and is vital in a variety of industries.

Thus the statement I is true.

• Pollutants emitted by incinerators that appear to have the potential to cause the largest health effects are particulate matter, lead, mercury, dioxins and furans.
• Incineration converts trash like paper, plastics, metals, and food scraps into bottom ash (the heavier ash residue) and fly ash (the lighter, more toxic ash, that is more likely to escape the incinerator's stack) which must be deposited in suitable landfills.

Thus statement II is true.

Therefore, the correct answer is both statements I and statement II are true.