Atmosphere

3. Meteors burn up and turn into shooting stars in the ____.
5. The ____ layer is found in the stratosphere.
6. The atmosphere protects from the Sun's harmful ___.
8. The Earth is believed to have formed 4.6 ___ years ago.
9. Meso means ____
11. If a meteor passes through the atmosphere and strikes the Earth, it is called a(n) ___.
12. The ___ that is present in today's atmosphere was formed when the first lifeforms on Earth performed photosynthesis.
14. The layer of the atmosphere that is closest to Earth
15. Oxygen is the ____ most abundant element in the atmosphere.
16. All ____, like storms and lightning, take place in the troposphere.
17. When earth Earth cooled, the water vapor condensed and formed the ___.

1. The outermost layer of the atmosphere is called.
2. Layer located between the mesosphere and the exosphere. Has the highest temperatures, but feels cold.
4. Volcanic eruptions filled the atmosphere with ____, carbon dioxide, and ammonia.
7. Early Earth was covered in volcanoes.
10. The most abundant element in the atmosphere is ____.
11. When an asteroid enters our atmosphere and begins to burn up, it becomes a ___.
13. Area found in both the mesosphere and the thermosphere where the aurora borealis occurs.