The correct Answer is Troposphere : Tropopause
Explanation
The Earth's atmosphere is divided into several layers based on temperature variations. Each layer has an upper boundary, which is a transition zone marking the limit of that layer.
Statement-wise Analysis
- Troposphere : Tropopause
- Correct. The troposphere is the lowermost layer of the atmosphere, and its upper limit is known as the tropopause. The tropopause is characterized by a cessation of the temperature decrease observed in the troposphere.
- Stratosphere : Mesopause
- Incorrect. The stratosphere is the layer above the troposphere. Its upper limit is the stratopause, not the mesopause. The mesopause is the upper limit of the mesosphere.
- Mesosphere : Stratopause
- Incorrect. The mesosphere is the layer above the stratosphere. Its upper limit is the mesopause, not the stratopause. The stratopause is the upper limit of the stratosphere.
- Thermosphere : Tropopause
- Incorrect. The thermosphere is the layer above the mesosphere. It does not have a distinct upper limit like the lower layers, but it extends to about 450 km. The tropopause is the upper limit of the troposphere.
Key Takeaway
The atmospheric layers (troposphere, stratosphere, mesosphere) are defined by specific temperature gradients, and their upper boundaries are distinct transition zones named tropopause, stratopause, and mesopause, respectively.