The correct option is 2 and 3 only.
Explanation
The atmosphere consists of different layers with varying density and temperature. The mesosphere is the third layer of the atmosphere, situated directly above the stratosphere and below the thermosphere.
Statement-wise Analysis:
- Statement 1 is Incorrect: The mesosphere lies above the stratosphere, not the thermosphere. It extends up to a height of approximately 80 km. The layer that extends from 80 km to 400 km is the thermosphere (containing the ionosphere).
- Statement 2 is Correct: In the mesosphere, temperature decreases with the increase in altitude. It is the coldest layer of the atmosphere, with temperatures dropping to approximately -100°C at its upper boundary.
- Statement 3 is Correct: The upper limit of the mesosphere is known as the mesopause. This boundary separates the mesosphere from the thermosphere above it.
Key Takeaway:
The mesosphere extends up to 80 km altitude, is characterized by decreasing temperatures with height, and is the layer where most meteorites burn up upon entering the Earth's atmosphere.