Question 70
Set 3
Contents
QQuestion
I. Rain forests produce more oxygen than that produced by oceans.
II. Marine phytoplankton and photo- synthetic bacteria produce about 50% of world's oxygen.
III. Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric air.
Which of the statements given above is/are correct?
OOptions
✓Correct Answer
DDalvoy Solutions
Analyzing statements about oxygen production on Earth:
I. Rain forests produce more oxygen than that produced by oceans: Incorrect. Oceans, particularly marine phytoplankton, produce significantly more oxygen than rainforests. Mature rainforests actually consume almost as much oxygen as they produce through respiration.
II. Marine phytoplankton and photosynthetic bacteria produce about 50% of world's oxygen: Correct. Marine phytoplankton are responsible for approximately 50-70% of global oxygen production through photosynthesis, making oceans the largest oxygen producers on Earth.
III. Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric air: Incorrect. Even well-oxygenated water contains much less dissolved oxygen than atmospheric air. Water can hold only about 8-10 mg/L of dissolved oxygen, while air contains about 21% oxygen by volume.
SUPSC Prelims Strategy and Tips
For oxygen production questions, remember that marine environments are the primary oxygen producers, not terrestrial forests. Also consider the physical limits of gas solubility in water versus air.