Question

Assertion (A): In a marine aquatic ecosystem, at any given time, the biomass of phytoplanktons (producers) is lower than the biomass of zooplanktons (primary consumers).

Reason (R): Phytoplanktons are consumed almost as rapidly as they are formed and thus have shorter life spans.

Options

• Both assertion (A) and reason (R) are true, and reason is the correct explanation of assertion.

• Both assertion (A) and reason (R) are true, but reason is not the correct explanation of assertion.

• Assertion (A) is true but reason (R) is false.

• Both assertion (A) and reason (R) are false.

Answer 1

Both assertion (A) and reason (R) are true, and reason is the correct explanation of assertion.

Explanation:

Phytoplanktons are consumed almost as rapidly as they are produced, so their standing crop biomass is smaller than that of zooplanktons. Thus the reason correctly explains the inverted biomass relationship.