The correct option is 2 and 3 only.
Explanation
The atmosphere consists of concentric layers of air defined by variations in temperature and density. The Mesosphere is the third major layer, situated between the Stratosphere and the Thermosphere.
- Statement 1 is Incorrect: The Mesosphere extends from approximately 50 km to 80 km above the Earth's surface. The layer that extends up to an average height of roughly 13 km (varying from 8 km at the poles to 18 km at the equator) is the Troposphere.
- Statement 2 is Correct: In the Mesosphere, temperature decreases with increasing altitude. This trend continues until the mesopause (the upper boundary of the Mesosphere), which is the coldest point in the Earth's atmosphere, with temperatures dropping to approximately -100°C.
- Statement 3 is Correct: The Mesosphere lies directly above the Stratosphere. The boundary separating the Stratosphere and the Mesosphere is called the Stratopause.
Key Takeaway: The Mesosphere is the atmospheric layer located between 50 km and 80 km altitude, characterized by a lapse rate where temperature decreases with height, reaching the atmosphere's minimum temperature at the mesopause.