The troposphere is the lowest layer of Earth's atmosphere. It starts at the surface of the Earth and extends upwards to an average height of about 7 miles (11 kilometers).

Here are some key things to remember about the troposphere:

* Weather occurs here: All the weather we experience on Earth, like rain, snow, wind, and clouds, happens in the troposphere.

* Temperature decreases with altitude: As you go higher in the troposphere, the temperature gets colder.

* Contains most of the atmosphere's mass: The troposphere holds about 80% of the atmosphere's total mass.

* Important for life: The troposphere contains the oxygen we breathe and is where most of the planet's living things reside.

Let me know if you have any other questions about the troposphere!