When plants and animals decomposed, _________ is released in the air.
carbon dioxide
10
Respiration is the __________ of carbon dioxide, while photosynthesis is the sink.
source
10
The idea that the moon is a large asteroid that has been pulled into orbit around the Earth.
capture hypothesis
10
The idea that the Moon and Earth formed together, close to each other, at the same time.
co-formation hypothesis
10
The idea that a large object roughly the sane size and mass as the planet Mars collided with the Earth, releasing rocks that were pulled together to form the Moon.
collision hypothesis
10
The moon is covered by circular dips called __________.
craters
5
The roundness of the Moon suggests the Moon has formed and been made stable mainly due to its ___________.
gravity
5
An asteroid that enters the atmosphere.
meteor
5
The piece of rock left behind after a meteor collides with the Earth's surface.
meteorite
5
The hypothesis that explains mass extinction 65 million years ago.
Alvarez hypothesis
10
Any substance that has mass, which is usually made up of atoms or molecules.