The correct option is (c).
Explanation
The atmosphere is the gaseous envelope surrounding the Earth, held in place by gravity. It is a fundamental abiotic component of the environment that interacts with the lithosphere and hydrosphere to create conditions suitable for the biosphere.
Statement-wise Analysis
- Statement 1 is Incorrect. The atmosphere is indispensable for life on Earth. It provides oxygen required for respiration by most living organisms and carbon dioxide essential for photosynthesis in plants. Furthermore, it acts as an insulating blanket, regulating planetary temperature by trapping heat (greenhouse effect) and preventing extreme temperature fluctuations between day and night.
- Statement 2 is Correct. The atmosphere protects life on Earth from harmful solar radiation. Specifically, the ozone layer found in the stratosphere absorbs the majority of the Sun's ultraviolet (UV) rays, which can cause skin cancer, cataracts, and damage to crops and marine life.
- Statement 3 is Correct. The atmosphere is a mechanical mixture of gases, not a chemical compound. Its composition is approximately 78% Nitrogen and 21% Oxygen, with the remaining 1% consisting of Argon, Carbon Dioxide, water vapour, and other trace gases.
Key Takeaway
The atmosphere is a life-sustaining mixture of gases that regulates Earth's temperature, provides essential elements for biological processes, and shields the planet from harmful cosmic and solar radiation.