AFOQT Practice Test

Which layer of the atmosphere is closest to Earth's surface?

1. Exosphere

2. Troposphere

3. Stratosphere

4. Mesosphere

The correct answer is: Troposphere

The troposphere is indeed the layer of the atmosphere closest to Earth's surface. It extends from the surface up to about 8 to 15 kilometers (about 5 to 9 miles), depending on geographic location and weather conditions. This layer is where we experience most of our weather events, including clouds, rain, and storms, due to its high concentration of water vapor and temperature variations. In the troposphere, the temperature typically decreases with altitude, which is opposed to what occurs in the layers above it. This makes it an essential layer for weather processes and climate. The other layers, while part of the atmosphere, are situated above the troposphere and do not play a role in the same way when it comes to weather and life on Earth.