Biology Bioenergetics SZABMU 2024
PMDC Verified Question 20 of 67
What is the concentration of \( CO_2 \) in air?
A
0.003-0.004%
B
0.03-0.04%
C
0.0003-0.0004%
D
3-4%
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: 0.03-0.04%
Concept:

Carbon dioxide is a crucial trace gas in the Earth's atmosphere, acting as the primary carbon source for global photosynthesis.

Solution:

  • Despite its massive biological importance, \( CO_2 \) makes up a tiny fraction of the standard atmospheric volume.
  • The universally taught biological baseline for atmospheric \( CO_2 \) concentration is approximately 0.03% to 0.04% (which equates to 300-400 parts per million).


Why other options are incorrect:

  • Options A and C represent concentrations that are far too low (plants would suffocate and die).
  • Option D (3-4%) is far too high and would be toxic to much of aerobic life while causing catastrophic global warming.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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