Choose the most appropriate option to describe the role of biogeochemical cycles. Class 9

Choose the most appropriate option to describe the role of biogeochemical cycles. Class 9

Revise, Reflect, Refine (Page 267-268)

Question 1.

Choose the most appropriate option to describe the role of biogeochemical cycles in an ecosystem. Class 9

(i) To provide food directly to all organisms.

(ii) To recycle essential nutrients between biotic and abiotic components.

(iii) To create new elements for use by living things.

(iv) To remove pollutants and toxins from the organism.

Answer:

(ii) To recycle essential nutrients between biotic and abiotic components.

Question 2.

Which of the following is primarily responsible for warming of the Earth? Class 9

(i) Solar radiation is immediately absorbed by carbon dioxide, which then releases it as heat.

(ii) The atmosphere’s tiny particles absorb incoming solar radiation, which directly heats the Earth.

(iii) The Earth’s surface absorbs solar radiation, which is then re-radiated and trapped by greenhouse gases.

(iv) The Earth’s environment is heated only by the solar radiation reflected by the clouds.

Answer:

(iii) The Earth’s surface absorbs solar radiation, which is then re-radiated and trapped by greenhouse gases.