Answer:
C. take stairs instead of the elevator
Explanation:
i hope this helped sorry if im wrong
1. Cardiovascular System
2. Muscular System
Answer: The heart consists of four chambers, two atria (upper chambers) and two ventricles (lower chambers). There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood.
Upper level because that’s where no one can see it but it is still good and far less expensive.
