Troposphere is the lowest layer of Earth's atmosphere and is where all weather occurs. It extends from the Earth's surface to an altitude of 8 to 14 km (5 to 9 miles).

The troposphere is characterized by decreasing temperature with increasing altitude, and it contains the air that we breathe. The temperature gradient in the troposphere is caused by the absorption of solar radiation by the Earth's surface, which heats the air near the ground. This warm air then rises, cools, and condenses to form clouds.

The troposphere is also the region of the atmosphere where most of the human activity occurs, including air travel, pollution, and weather events.

Functions of the troposphere:

* Contains the air that we breathe

* Regulates temperature through absorption of solar radiation and greenhouse gases

* Produces weather events such as clouds, rain, snow, and storms

* Supports air travel

* Disperses pollutants