AIIMS 2019 Botany Primary Productivity Assertion Reason Question
The total amount of organic matter synthesized by producers per unit time and per unit area, in the process of photosynthesis is called as gross primary productivity (GPP). Primary productivity is high and sustained throughout the year in the tropical area while it is limited in temperate area by cold climate and small growing period. Maximum sunlight is available in tropics whereas poles receive minimum sunlight. Due to this, photosynthesis is maximum and net primary productivity (NPP) is highest (>20 t ha⁻¹ year⁻¹) in tropics against average (8 t ha⁻¹ year⁻¹) in temperate forests. So, the correct answer is 'Both Assertion and Reason are incorrect'.
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
Assertion is correct but Reason is incorrect
Both Assertion and Reason are incorrect
Correct Answer
Detailed Explanation
Option D is correct because both the assertion and the reason contain inaccuracies regarding primary productivity. Gross primary productivity (GPP) is indeed highest in tropical regions, but the statement that net primary productivity (NPP) is always greater than 20 t ha⁻¹ year⁻¹ in the tropics is misleading, as NPP can vary significantly based on specific environmental conditions. Other options are incorrect because they either assert the correctness of the reasoning or the assertion without acknowledging these inaccuracies, which misrepresents the dynamics of photosynthesis and productivity across different biomes. Understanding the factors influencing GPP and NPP, such as sunlight availability and climate, is crucial for grasping ecosystem productivity.
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