IAS Prelims Exam: Physical Geography NCERT Questions: LIFE ON EARTH

For the Civil Services IAS Exam Geography has vast and it covers most sections of the General Studies for the IAS Prelims Exam. The geography is scientific in its orientation and hence the IAS Aspirants having Arts background find it very difficult to prepare the geography for the IAS Prelims Exam

Q1. Which of the following is/are true about ecology?
1.  Study of interaction between living organisms
2. Study of interaction between living organisms and physical environment
3. Study of development and evolution of organisms

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: b

Explanation: The study of interactions between life forms (biotic) and the physical environment (abiotic) is the science of ecology. Hence, ecology can be defined as a scientific study of the interactions of organisms with their physical environment and with each other.

Q2. Habitat of environment includes which of the following factors?
1. Physical factors
2. Chemical factors
3.  Biotic factors

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: b

Explanation: A habitat in the ecological sense is the totality of the physical and chemical factors that constitute the general environment. A system consisting of biotic and abiotic components is known as ecosystem.

Q3. Which of the following is/are types of biomes?
1.  Grassland
2.  Aquatic
3. Altitudinal

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer:  d

Explanation: There are five major biomes — forest, desert, grassland, aquatic and altitudinal biomes.

Q4. In the atmosphere much of the oxygen is produced by, which of the following?
1. Transpiration
2.  respiration
3. Photosynthesis

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer:b

Explanation: Much of oxygen is produced from the decomposition of water molecules by sunlight during photosynthesis and is released in the atmosphere through transpiration and respiration processes of plants.

Q5. Which of the following is/are not principal geochemical component of biosphere?
1. Hydrogen
2. Nitrogen
3. Carbon

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: d

Explanation: Other than carbon, oxygen, nitrogen and hydrogen being the principal geochemical components of the biosphere, many other minerals also occur as critical nutrients for plant and animal life.

Q6. Nitrogen is essential constituent of which of the following organic compounds?
1. Nucleic acids
2.  Amino acids
3. Vitamins

Select the correct answer from the following codes
a.    Only 1
b.    Only 1 and 2
c.    Only 2 and 3
d.    1,2 and 3

Answer: d

Explanation: Nitrogen is a major constituent of the atmosphere comprising about seventy-nine per cent of the atmospheric gases. It is also an essential constituent of different organic compounds such as the amino acids, nucleic acids, proteins, vitamins and pigments.

Q7. Consider the following statements
1. Nitrogen cannot be utilised by any species directly in gaseous form.
2. Apart from certain soil microorganism, certain marine animals can also do nitrogen fixing.

Select the correct answer from the following codes
a. Only 1
b. Only 2
c. Both 1 and 2
d. Neither 1 nor 2

Answer: b

Explanation: Only a few types of organisms like certain species of soil bacteria and blue green algae are capable of utilising it directly in its gaseous form. Nitrogen can also be fixed in the atmosphere by lightning and cosmic radiation. In the oceans, some marine animals can fix it.

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