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The correct answer is Aorta.

Key Points

• The Aorta is the largest artery in the body.
• The Aorta begins at the top of the left Ventricle which is the Heart's muscular pumping chamber.
• The Heart pumps blood from the left ventricle into the Aorta through the Aortic valve.

Additional Information

• Coronary arteries carry oxygenated blood to the muscles of the heart.
• Any type of hindrance in Coronary arteries causes a heart attack.
• The Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
• The pulmonary artery contains impure blood.
• Pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the left atrium of the heart.

• The left ventricle pumps oxygenated blood into the aorta via the tricuspid aortic valve.
• The right atrium receives deoxygenated blood from the vena cavae and coronary sinus and empties it into the right ventricle.
• The right ventricle pumps deoxygenated blood into the pulmonary trunk via the pulmonary valve.
• The left atrium receives oxygenated blood from pulmonary veins and empties it into the left ventricle.

The correct answer is Frog

Key Points 

• External fertilization occurs when eggs are shed by the female and fertilized by the male outside of the body. This type of fertilization is common in aquatic organisms, such as fish and amphibians.
• Among options (hen, cat, frog, and snake), the frog is an example of a species where external fertilization takes place. The other listed animals - hen (a species of bird), cat (a mammalian species), and snake (a species of reptiles) - practice internal fertilization.

Primary pollutant: Pollutants which are emitted directly from the identifiable sources, either from the natural hazardous events like dust storms, volcanoes, etc or from human activities like burning of wood, coal, oil in homes or industries or automobiles, etc.

The important primary air pollutants are:

1. Oxides of sulphur, particularly the sulphur dioxide (SO₂);
2. Oxides of carbon like carbon monoxide (CO) and carbon dioxide (CO₂), particularly the carbon monoxide (CO);
3. Oxides of nitrogen, like NO, NO₂, NO₃ (expressed as NO_x);
4. Volatile organic compounds, mostly hydrocarbons; and
5. Suspended particulate matter (SPM).

These primary pollutants often react with one another or with water vapour, aided and abetted by the sunlight, to form entirely a new set of pollutants, called the secondary pollutants.

These are the chemical substances, which are produced from the chemical reactions of natural or anthropogenic pollutants or due to their oxidation, etc., caused by the energy of the sun.

The important secondary pollutants are:

(i) Sulphuric acid (H₂SO₄);

(ii) Ozone (O₃);

(iii) Formaldehydes; and

(iv) Peroxy-acyl-nitrate (PAN); etc.

Primary Pollutants: Co, CO₂, SO_X, NO_X, Aerosols, Bacteria, Pollens, Suspended particulates, Fly ash, Mist, Dew, Mist, Soot, Volcanoes, etc.

Secondary Pollutants: Chlorofluorocarbon, Ozone, Smog, Acid rain (H₂SO₄, HNO₃, H₂CO₃), PAN (Peroxyacetyl Nitrate), PBN (Peroxybutyl Nitrate), PPN (Peroxypropyl Nitrate)

The correct answer is Nuclear reactions.

Key Points

• The mass can neither be created nor be destroyed but is transformed from one form to another, this law is known as the law of conservation of mass.
• According to this law, the mass of products in the reaction is equal to the mass of the reactants.
• The nuclear reaction does not follow the law of conservation of mass since a particle, with a definite mass, is thrown away from the reactants.
• An example of a nuclear reaction is the splitting of the uranium-235 nucleus when it is bombarded with the nucleus.

Additional Information

• The Law of conservation of energy states that energy can neither be created nor be destroyed, but is transformed from one form of energy into another form of energy.
• The reaction in which heat is evolved is called an exothermic reaction.
• The reaction in which heat is required to start the reaction is called an endothermic reaction.

The Correct answer is that Non-metallic oxides are basic in nature.

 Concept:

Metals: 

• The elements readily form positive ions (cations) and are called Metals.Ex.→ Na, K, Mg, Fe, Cu, Ag, etc.
• Metals are usually Solid, a good conductor of Heat & Electricity, Malleable, Ductile, and Sonorous, and Have good tensile strength.
• Metals react with oxygen to form their respective Metal Oxides i.e. Metal + Oxides →  Metal Oxides

Non-Metals: 

• Non-Metals form Negative ions by accepting or gaining electrons.
• They are Insulators, Have Lower Tensile Strength, and Dull Appearance.

Explanation:

• To test the acidity and basicity of these Metal Oxides, they are made with water & then react with water, and then tested with litmus paper.
• A basic solution turns litmus to blue whereas an acidic solution turns blue litmus to red.
• Metal Oxides + Water → Metal Hydroxides
• Metal oxides are Basic in nature.
• Some Metal Oxides, for example, Oxides of Aluminum and Zinc show both acidic and basic nature Such Oxides are called Amphoteric Oxides.
• Non-metallic oxides are Acidic in nature. Ex.→ SO2 + H2O → H2SO4 + 2H .
• The basic solution has more OH - ion concentration than the H+ ion.

The correct answer is 2.

Key Points

• The carbon atom is tetravalent even though it has unpaired electrons.
• It is determined that the floor kingdom of a neutral carbon atom does indeed contain two unpaired electrons.
• The Co2+ ion in an aqueous answer is octahedrally coordinated and paramagnetic, with 3 unpaired electrons.

Additional Information

• Carbon can shape 4 covalent bonds.
• The helium atom incorporates 2 electrons.
• A carbon atom can bond with four different atoms and is like the four-hollow wheel, even as an oxygen atom,

The correct answer is rolling friction.

Key Points

• For a moving solid body, there are 2 principal types of friction are following
• Rolling friction
• Sliding friction
• On a surface, The force resisting the motion of a rolling body is known as Rolling resistance or Rolling friction.
• The Rolling of a wheel or ball on the ground is an example of Rolling friction.
• In Sliding friction, there is a restriction on the movement of the body as only one side of the body is in contact with the surface.
• An example of Sliding friction is Pushing a box across the table.
• Rolling resistance is weaker than sliding friction.

Additional Information

• When 2 surfaces are rubbed against each other, Sliding friction takes place.
• When an object rolls on the surface, Rolling friction takes place.
• Because of rolling friction, A basketball rolled on the court will eventually come to a halt.
• A broad-tire bike will burn extra fuel because of the increased Rolling friction.

The correct answer is decrease.

Concept:

Friction force:

• Friction is the force that resists motion when the surface of one object comes into contact with the surface of another.
• It is a force that opposes the relative motion of two bodies in contact.
• The frictional force acts in a direction opposite to the direction of motion of the bodies in contact.
• Frictional force prevents objects from gliding and ensures contact.
• Friction forces also provide a significant amount of resistance to motion.

Lubricant:

• It is a substance used for lubricating an engine or component, such as oil or grease.
• ​There are 4 types of lubricants i.e., Oil, Grease, Penetrating Lubricants, and Dry Lubricants.
• It aims at reducing friction between two moving objects.

Explanation:

• Friction force acts according to Newton's third law of motion.
• To perform a motion, the force used to initiate it must be greater than the frictional force.
• If we apply oil to the door hinges, the friction will decrease because lubrication always decreases friction between two surfaces.
• Oil can be any type of lubricant.
• For example, molybdenum sulphide and graphite.

Thus, if we apply oil on door hinges, the friction will decrease.

The correct answer is Electrolytic Refining.

Key Points

• Electrolytic refining is a technique employed for the extraction and purification of impure metals through electrolysis.
• In this process, the crude metal serves as the anode, while a strip of pure metal is utilized as the cathode, and a soluble salt of the same metal is employed as the electrolyte.
• Upon passing an electric current, metal ions from the electrolyte are deposited as pure metal onto the cathode, while the impure metal from the anode dissolves into ions within the electrolyte.
• Beneath the anode, the impurities of metals accumulate, forming what is known as anode mud.
• This method facilitates the separation and removal of impurities, resulting in the production of refined and high-purity metals.

Important Points

• Vapor-phase refining is a purification technique utilized to convert crude metals into volatile compounds.
• Poling is a metallurgical method employed to purify metals containing oxidized impurities.
• Liquation is a metallurgical method used for separating metals from an alloy or ore.

The correct answer is All of the above.

Key Points

• Due to gravitational force

1. We are attracted towards the earth's centre
2. Tide Occurs
3. Earth revolves around the sun

• The gravitational force of attraction between a satellite and the earth gives rise to centripetal force.
• Earth satellites are objects which revolve around the earth.
• Their motion is very similar to the motion of planets around the Sun and hence Kepler’s laws of planetary motion are equally applicable to them.
• In particular, their orbits around the earth are circular or elliptic.
• Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy including planets, stars, galaxies, and even light are attracted to one another.
• On Earth, gravity gives weight to physical objects, and the Moon's gravity causes the tides of the oceans.
• The artificial satellites orbiting the Earth remain in their orbits and do not fall down due to the attraction of the Earth (gravity) which provides the necessary centripetal acceleration.

Additional Information 

• Satellite is revolving around the earth
• Fg = Gravitational force of satellite towards the earth
• Fc = Centrifugal force on the satellite
• Fg = Fc makes Fnet = zero.
• Thus net force acting on the satellite is zero.
• When the body is inside a satellite, which is orbiting around the earth, the gravitational pull on the body due to earth is balanced by the centrifugal force on the body, due to which the effective weight of the body becomes zero.
• The force exerted by the satellite floor on the astronaut is equal to zero.
• He is not attracted by gravitational force.