Search Previous Year Questions

Correct answer is Priestly

Key Points

• The Bell Jar Experiment.
• J. Priestley (1772) carried out very interesting experiment on Bell jar, rat, pudina or mint and candle. He came to conclude that plants purify air (burning of candles), and gaseous exchange occurs during photosynthesis.

Priestley observed that a candle burning in a closed space – a bell jar, soon gets extinguished.

• Similarly, a mouse would soon suffocate in a closed space. He concluded that a burning candle or an animal that breathe the air, both somehow, damage the air. But when he placed a mint plant in the same bell jar, he found that the mouse stayed alive and the candle continued to burn.
• Priestley hypothesized as follows: Plants restore the air which breathing animals and burning candles remove.

correct answer is Zinc

Key Points

The metal complexes produced during the leaching process are reduced using Zinc methods

• Ferrous material: Ferrous metals are those in which chief constituent is iron, although other constituents like carbon, manganese, phosphorus and sulphur etc. Example steel and cast iron
• Non-ferrous metals are those which do not contain iron. Metals like copper, zinc, aluminum, lead, tin, etc, and their alloys.

The correct answer is 40 billion 

Key Points

• A United Nations 2014 report stated, “in Sub-Saharan Africa, people spent 40 billion hours a year collecting water, equivalent to a year’s worth of labour by the entire workforce of France.”
• Women, children and most young girls are responsible for obtaining water for their families.
• In Africa, when People's main responsibility is to gather water, the back-breaking hours and 4-6 mile walk, sometimes performed 2-3 times per day, prevents many from getting an education.

The correct answer is sponges.

Key Points

• Sponges have cellular-level organization, meaning that, 
• Their cells are specialized so different cells perform different functions.
• Similar cells are not organized into tissues and bodies are a sort of loose aggregation of different kinds of cells.
• Sponges
• Sponges, the members of the phylum Porifera, are a basal animal clade as a sister of the diploblastic.
• They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells.

Additional Information

• Annelids are segmented worms with a tubular body and a specialized digestive system with a terminal mouth and an anus.
• The flatworms or Platyhelminthes are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates.
• Nematodes are parasites of animals and occur in almost all organs of the body, but the most common sites are in the alimentary, circulatory, and respiratory systems.
• Chordates are animals that bear notochord.
• It has a dorsal hollow nerve chord.
• It has pharyngeal gill slits.
• It has a ventral heart.
• Phylum Chordata comprises Urochordata, Cephalochordata, and Vertebrata.

Correct answer is Wadis.

Key Points

• Wadis 
• Wadi Oued, is the Arabic term traditionally referring to a valley. In some instances, it may refer to a wet  riverbed that contains water only when heavy rain occurs.
• Wadis, as drainage courses, are formed by water, but are distinguished from river valleys or gullies in that surface water is intermittent or ephemeral.
• Wadis are generally dry year round, except after a rain. The desert environment is characterized by sudden but infrequent heavy rainfall, often resulting in flash floods.
• Wadis tend to be associated with centers of human population because sub-surface water is sometimes available in them.

The correct answer is Forebrain.

Key Points 

• Structure of the Brain: For the convenience of study, the brain can be divided into three parts: Hindbrain, Midbrain, and Forebrain
• Forebrain:
• It is considered to be the most important part of the brain because it performs all cognitive, emotional, and motor activities.
• Four major parts of the forebrain: are the hypothalamus, thalamus, limbic system, and cerebrum.
• Hypothalamus is the master of master glands and controls the secretion released by the pituitary glands.
• It releases releasing hormones that instruct the pituitary to secrete its hormone and also secretes inhibiting hormones that inhibit the release of hormones from the pituitary.

Additional Information 

• Hindbrain
• This part of the brain consists of the Medulla Oblongata,  and Cerebellum.
• Midbrain:
• The midbrain is relatively small in size and it connects the hindbrain with the forebrain.
• A few neural centers related to some special reflexes and visual and auditory sensations are found here.
• An important part of the midbrain, known as the Reticular Activating System (RAS), is responsible for our arousal.
• It makes us alert and active by regulating sensory inputs. It also helps us in selecting information from the environment.
• Cerebellum:
• It is part of the hindbrain.
• It helps in maintaining body posture.
• It consists of white and grey matter.

Correct answer is Host properties

Key Points

• Consumers 
• From simple organic materials like carbon dioxide and water, animals are not able to make their own food and hence depend on other organisms for food.
• This type of system is called host nutrition system.
• Therefore, organisms that depend on other organisms for food are known as heterotrophs or 'heterotrophs'
• Examples are humans, dogs, cats, etc., and some non-green plants such as yeast. Basically, heterotrophs depend on plants or other organisms for their food.

Additional Information

• Carnivorous
• These consumers are at the apex position of the food chain cycle.
• They mostly eat meat. Thus, they are considered Carnivorous.
• For example tiger, lion, shark, etc.
• Herbivores 
• The herbivores are animals that only eat plant and plant products.
• For example: cow, deer, sheep, buffalo, grasshoppers, butterfly, etc. Thus, Buffalo is a Herbivorous animal.
• Omnivore
• These organisms obtain food by feeding on both plants as well as animals
• Omnivorous plays an important role in maintaining a healthy ecosystem by recycling waste. Examples of omnivores include Humans, Bears, Birds,etc..

The correct answer is option 4

Key PointsAs per the Technical Training Manual for the SBM

Components of Toilet: Every Toilet has two major component

• Substructure: Substructure is technically important as it provides safe disposal or reuse of human waste. All technical options are meant for substructures only.
• Superstructure: The superstructure basically provides privacy. There may be a wide range of types of superstructures for the same type of sub-structure, depending on the economic status of the beneficiaries.

correct answer is Kariz

Key Points

• Kariz
• A kareez is a combination below and above ground channel system used to bring water to a settlement or fields from a natural source, say an aquifer, mountain spring or lake.
• Many of the kareez / qanats are ancient and their history is intertwined with the history of Aryan lands. Importantly, the system was sustainable and did not exhaust underground aquifers.
• A jube is an above ground gutter (drain, ditch, or rain sewer). Frequently, communities that construct and use the kareez, also employ the jube as part of an urban water collection and management system.
• Jubes collect rain water in those areas with a significant enough amount of precipitation to cause a run-off. Water collected in this manner, while probably not suitable as drinking water is useful as irrigation water. In Persian, a spring is called sarab meaning the head or start of water or stream or cheshmeh.

correct answer is Reduction

Key Points

Reduction is the process which includes

• Gain/addition of electrons or
• Removal of oxygen atom in a molecule or
• Addition of hydrogen atom in a molecule.

Loss of electrons and increase in the oxidation state is the characteristics of an oxidation reaction.

For example

• H2S + Cl2 → 2HCl + S
• In this reaction, the chlorine is getting reduced to hydrochloric acid (HCl) on addition of hydrogen provided by Hydrogen sulphide (H2S).

Additional Information

• Crystallization
• Crystallisation is an example of physical change.
• It involves separation of solid-liquid separation technique, which involves the transfer of solute to the pure solid crystalline phase from the liquid solution.
• And it’s related to physical change as it doesn’t involve formation of any new substance.
• Oxidation
• Oxidation Reaction refers to a reaction in which either the addition of Oxygen takes place or the removal of Hydrogen takes place.
• It can also be said as the process of loss of one or more electrons by atoms or ions.
• Example is:

2Mg + O2 = 2MgO