Answer:
It connects the brain to the rest of the body.
Answer:the job of that is to let nutrients or good things inside and keep the unwanted out. To make sure what the cell needs to survive and reproduce
Explanation:hope this helps
Answer:
Every cell of the body needs oxygen for the process of cellular respiration by which the energy in food is converted into energy that can be used by the body's cells. During cellular respiration, glucose and oxygen are converted into carbon dioxide and water, and the energy is transferred to ATP.