Question

Assertion (A): Gross primary productivity is always less than net primary productivity.
Reason (R): Rate of synthesis of organic matter by consumers is known as secondary productivity.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Remember: GPP > NPP and secondary productivity refers to consumers, not producers.

Answer 1

The Correct Option is C

Step 1: Gross primary productivity (GPP) is the total energy fixed by autotrophs.
Step 2: Net primary productivity (NPP) = GPP - Respiration (R). So, NPP is always less than GPP.
Step 3: Reason talks about consumers, but Assertion is about producers.
Step 4: While Reason is a correct definition, it does not support or explain the Assertion—it refers to a different concept.
\[ \Rightarrow \text{Assertion is true, but Reason is unrelated.} \Rightarrow \boxed{\text{Correct answer: (C)}} \]