Question

Choose the correct statement.

• A. Annual NPP of land area is higher than oceans.
• B. NPP is greater than GPP in terrestrial ecosystems.
• C. Secondary productivity is always higher than Primary productivity in Oceanic ecosystem.
• D. Primary productivity is unaffected by environmental factors.

Hint:

Land NPP is about 115 and ocean NPP is about 55 billion tons.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
Find the one true statement.

Step 2: Numbers test:
From the passage, land is 170 - 55 = 115 and the ocean is 55, so land is greater.

Step 3: Energy flow test:
Energy drops at each trophic level, so consumers cannot out-produce plants. Option 3 fails.

Step 4: Definition test:
NPP = GPP - R, where R is respiration. R is positive, so NPP is smaller. Option 2 fails.

Step 5: Dependence test:
Plant growth changes with light, water and nutrients. Option 4 fails.

Step 6: Result:
Only option 1 survives.

Final Answer:
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