Question

The role of plants in the carbon cycle is:
I. Release carbon dioxide into the atmosphere.
II. Remove carbon dioxide from the atmosphere.
III. Fix carbon dioxide in root nodules.

• A. I only
• B. II only
• C. III only
• D. I and II only
• E. I, II and III

Answer 1

The correct option is D I and II only

Green plants capture light energy and convert it into chemical energy by the process of photosynthesis. During photosynthesis, carbon dioxide and water are transformed into simple carbohydrates, and oxygen is liberated into the atmosphere. In the daytime, plants use the carbon dioxide from the atmosphere and from respiration for the process of photosynthesis. But at night time, the carbon dioxide released by the plants during respiration goes directly into the atmosphere. This is because there is no photosynthesis at night, to absorb the carbon dioxide.

Hence the role of plants in the carbon cycle is to release carbon dioxide in the atmosphere and to remove carbon dioxide from the atmosphere.

So, the correct answer is 'I and II only'.