POLL ANSWERS WITH EXPLANATION 28.7.2020

1.) Which of the following are the direct consequences of Mercury poisoning?

i. Affects the nervous system.
ii. Affects the development of foetuses.
iii. Degenerates renal cells

A. i only
B. ii only
C. i and ii only
D. i, ii and iii.

Ans: C

Explanation: Mercury poisoning interferes with the nervous system and development of foetuses.

2.) Consider the following statements with regard to Bio-geochemical cycles –

i. The flow of energy in ecosystems is uni-directional.
ii. Oxygen, carbon, hydrogen and nitrogen are needed in small quantities to sustain life and hence they are known as micronutrients.
iii. In gaseous cycles the reservoir pool is the atmosphere and in sedimentary cycles the reservoir pool is the Earth’s crust

Which of the above statements are true?

A. i only
B. iii only
C. Both i and ii
D. Both i and iii.

Ans: D

Explanation: Oxygen, carbon, hydrogen and nitrogen are needed in large quantities to sustain life
and hence they are known as macronutrients.

3.) Upwelling of ocean currents plays a role in which of the following bio-geochemical cycles?

A. Carbon cycle
B. Phosphorous cycle
C. Nitrogen cycle
D. Oxygen cycle

Ans: B

Explanation: Phosphorus is removed from the reservoir pool due to surface run-off and gets deposited on the ocean floor as sediments and it is brought back to the reservoir pool by upwelling ocean currents. These bring phosphorus to the surface waters, where it is taken into marine food chains.

4.) Consider the following statements with regard to Ecological succession –

i. Ecological succession is the process of change in the species structure of an ecological community over time.
ii. Ecological succession leads to a stable, self-perpetuating community, called the seral stage.
iii. Secondary succession is faster than primary succession

Which of the above statements are true?

A. i only
B. iii only
C. Both i and ii
D. Both i and iii.

Ans: D

Explanation: Each stage in the ecological succession process is known as a seral stage whereas the stable, self-perpetuating community that is established at the end is known as the climax.

5.) Biotic potential of a species is determined by –

i. reproductive span of the species
ii. frequency of reproduction
iii. litter size
iv. survival rate

A. i only
B. ii and iii only
C. iii and iv only
D. i, ii, iii and iv

Ans: D

Explanation: The maximum rate at which a population can increase when resources are unlimited and environmental conditions are ideal is termed as the population’s biotic potential. It is determined by all the four factors.

Leave a Reply

Your email address will not be published. Required fields are marked *