A major and top source of oxygen in the atmosphere is—
- APhotosynthesis by forest plants
- BPhotosynthesis by Oceanic plants
- CPhotosynthesis by grassland ecosystems
- DMore than one of the above
- ENone of the above
Show answer and explanation
Correct answer: (d) More than one of the above
Explanation
The atmosphere is one of the main components of the Earth’s interdependent physical systems. The Earth’s atmosphere is composed of approx 78% nitrogen (N2), 21% oxygen (O2), and 1% other gases. Major sources of oxygen include photosynthesis by forest plants, marine plants, and plants in grassland ecosystems.