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Everyday Science Easy PMS Uploaded: 01 Sep 2026

The main source of atmospheric oxygen is:

  • A Animals
  • B Volcanic eruptions
  • C Ocean currents
  • D Photosynthesis by plants
Correct Answer: Option D — Photosynthesis by plants
Explanation:
Photosynthesis carried out by plants, algae, and cyanobacteria releases oxygen as a byproduct, replenishing the Earth's atmospheric oxygen supply.
Submitted by: PaperMCQs
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