The correct option is (c) 1 and 3 only.
Explanation
The atmosphere is composed of a mixture of gases that sustain life on Earth. The relative abundance of these gases is fixed in the lower atmosphere, with Nitrogen and Oxygen being the primary constituents. The exchange of gases between the atmosphere and living organisms is governed by processes such as photosynthesis and respiration.
Statement-wise Analysis
- Statement 1 is Correct: Nitrogen is the most abundant gas in the Earth's atmosphere, constituting approximately 78% of the total volume. Oxygen follows as the second most plentiful gas at approximately 21%.
- Statement 2 is Incorrect: During the process of photosynthesis, green plants inhale (absorb) Carbon Dioxide and exhale (release) Oxygen. Plants consume Oxygen primarily during respiration, not photosynthesis.
- Statement 3 is Correct: Humans and animals inhale Oxygen and release Carbon Dioxide during respiration. This released Carbon Dioxide is essential for green plants, which utilize it to synthesize food through photosynthesis, thereby maintaining the balance of atmospheric gases.
Key Takeaway: Nitrogen is the most plentiful atmospheric gas. The biological gas cycle involves plants absorbing Carbon Dioxide and releasing Oxygen during photosynthesis, while animals absorb Oxygen and release Carbon Dioxide during respiration.