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

The layer of the Earth's atmosphere that is closest to the surface is the troposphere. This layer extends from the Earth's surface up to about 8 to 15 kilometers (5 to 9 miles) high, depending on geographical location and weather conditions.

The troposphere is where all weather phenomena occur, such as clouds, rain, and storms, making it crucial for life on Earth. This layer contains the majority of the atmosphere's mass, including water vapor, which plays a key role in weather processes. As we move upwards from the troposphere into the next layers, such as the stratosphere, mesosphere, and thermosphere, the temperature and pressure decrease significantly.

In contrast, the other options represent different layers of the atmosphere that are situated higher above the Earth's surface. The stratosphere lies above the troposphere and contains the ozone layer, which absorbs and scatters ultraviolet solar radiation. The mesosphere is even higher and is known for its decreasing temperatures with altitude, playing a role in the breakdown of meteors entering the atmosphere. The ozone layer itself is a part of the stratosphere, but it is not a separate layer that is distinct from the stratosphere. Therefore, the troposphere is