Life is possible on Earth due to the presence of liquid water, a suitable temperature range, a protective atmosphere containing oxygen, and its optimal distance from the Sun.

Here are the answers to your questions:

1. Life is possible on Earth due to the presence of liquid water, a suitable temperature range, a protective atmosphere containing oxygen, and its optimal distance from the Sun.

2. Days and nights are formed by the Earth's rotation on its axis. As the Earth spins, the side facing the Sun experiences day, while the side facing away experiences night.

3. The atmosphere is a layer of gases that surrounds a planet or other celestial body. Earth's atmosphere is composed mainly of nitrogen and oxygen, along with other gases, and is held in place by gravity.

4. Earth is called a unique planet because it is the only known planet in our solar system that supports life. This is due to its unique combination of liquid water, a breathable atmosphere, and moderate temperatures.

5. Revolution refers to the movement of one celestial body around another in an orbit. For example, the Earth's revolution around the Sun takes approximately 365 days, causing the change of seasons.