Biology Homeostasis PMDC Conceptual Practice
PMDC Verified Question 50 of 99
During active daytime photosynthesis, autotrophic green plants release which gaseous by-product into the atmosphere?
A
\(\text{O}_2\)
B
\(\text{CO}_2\)
C
\(\text{H}_2\text{O}\) vapor
D
\(\text{N}_2\)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: \(\text{O}_2\)
Concept: Plant photosynthetic gas exchange.

Solution: During light-dependent reactions of photosynthesis, photolysis of water splits \(\text{H}_2\text{O}\), releasing molecular oxygen (\(\text{O}_2\)) as a metabolic by-product.

Why other options are incorrect:
  • Option B (\(\text{CO}_2\)): Carbon dioxide is consumed during the Calvin cycle, not produced as a photosynthetic waste.

  • Option C (\(\text{H}_2\text{O}\)): Transpired water vapor is a physical evaporative loss rather than a photosynthetic chemical waste product.

  • Option D (\(\text{N}_2\)): Atmospheric nitrogen is inert and not produced by photosynthesis.

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