Earth is approximately spherical in shape like all planets and stars. Earth is composed mostly of rock. Three-fourths of its surface is covered by a relatively thin layer of water (some of it frozen), and the entire planet is surrounded by a relatively thin blanket of air.
I think it’s b because it helps the blood cells enable more oxygen and takes it to the muscles
Hope that help
Answer: I just finished a health class last semester so I am willing to help you and direct you to some useful sites.
Hope this helps! :)
Explanation:
I am stuck on this question as well. Did you get the answer?
