Which atmospheric layer lies directly above the troposphere?

• A. Troposphere
• B. Stratosphere
• C. Mesosphere
• D. Thermosphere

Answer: (B)

The main idea here is the vertical structure of Earth's atmosphere and where each layer begins and ends. The troposphere is the lowest layer where weather occurs and temperatures generally fall with height. The boundary at the top of this layer is called the tropopause, which marks the start of the next layer.

Directly above the troposphere is the stratosphere. This layer is characterized by a temperature profile that increases with altitude, due to the absorption of ultraviolet radiation by the ozone layer contained within it. That temperature rise with height creates a more stable, layered region with less vertical mixing than in the troposphere, which is why this layer is distinct from the one below.

To put it in context, after the stratosphere come the mesosphere and then the thermosphere, with their own temperature trends and characteristics, gradually giving way to the outer exosphere. Knowing the order helps explain why weather stays confined to the lowest portion of the atmosphere while commercial flights often climb into the lower stratosphere to avoid turbulence.