Unit 4

_______ are pieces of rock and metal that orbit the sun.

• Atmosphere

• Galaxy

• Asteroids

Earth has an ______ of gases around it.

• orbit

• atmosphere

• asteroids

Eight planets and the sun are in our ______.

• solar system

• comet

• atmosphere

A _____ is a group of stars, planets, gases, and dust.

• comet

• galaxy

• orbit

A ____ is a ball of ice and dust.

• asteroids

• solar system

• comet

____ is tiny pieces of dirt.

• Galaxy

• Dust

• Orbit

Earth and seven other planets _____ the sun.

• solar system

• comet

• orbit

Earth is part of the Milky Way _____.

• galaxy

• solar system

• orbit

• atmosphere

The sun is at the center of our _____.

• Milky Way

• atmosphere

• solar system

• galaxy

Oxygen and other gases make up Earth's _____.

• asteroids

• craters

• atmosphere

• poisonous gas