Since the blood is moving out of the heart by the left ventricle and aorta the blood needs to get pumped and circulated through the heart. More it contracts the better circulation of blood throughout the body!
"Send a robot to measure how much oxygen is dissovled in ocean water at various depths, because the amount of oxygen dissovled in water changes with pressure" <–– the answer
<span>Scientists use models of natural systems because these systems are often too large, too small, or too complex to study directly</span>
Answer:
Apprentice to a residential electrician.
Explanation: