Answer:
For early earth, it was filled with loads of oxygen and could kill humans if they breathed the oxygen that was in the air about 100 million years ago. This massive amount of oxygen cause massive creatures like the dinosaurs to exist. Current earth has an atmosphere with not too much oxygen.
Explanation:
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I do not know at ALL. =( Sorry.
The answer would be letter A. globular cluster. This group of very old stars that are clustered together in a spherical in shape and can contain from 10,000 to several million is called a globular cluster. In our galaxy, there are 150 globular clusters.
It is important because it breaks down the food eaten by the animals into nutrients which are needed for their bodies to function well. Not only it is important to animals but also to humans. <span>Food and drink must be changed into smaller molecules of nutrients before the blood absorbs them and carries them to cells throughout the body.</span>