Civil Services Examination · প্রশ্ন 20

With reference to the planet Earth, consider the following statements: 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?

I and II
II only
I and III
None of the above statements is correct

উত্তর দেখান ও ব্যাখ্যা

উত্তর: (B) II only

ব্যাখ্যা

Oceans (via phytoplankton/bacteria) produce roughly half of Earth's oxygen — more than rainforests; dissolved oxygen in water is actually far lower in concentration than in air.