What is the approximate concentration of oxygen present in Earth’s atmosphere?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 21%
- The approximate concentration of oxygen in Earth’s atmosphere is about 21% by volume.
- Oxygen is the second most abundant gas in the atmosphere after nitrogen, which makes up around 78%.
- This 21% level is crucial for supporting life, especially for respiration in humans and animals, as well as for combustion processes.
- The remaining portion of the atmosphere consists of argon, carbon dioxide, and trace gases.
- This composition has remained relatively stable due to natural processes like photosynthesis, which continuously replenishes atmospheric oxygen, and respiration and decomposition, which balance its usage.
- This equilibrium helps sustain Earth’s ecological and biological systems.