Answer:
circulatory
Explanation:
Heart is only responsible for generating the pumping force needed to supply blood to each and every corner of the body. As heart is part of circulatory system. The answer is Circulatory system.
A. It has mass.
Air is matter, and can't be seen thus not all matter can be seen.
Any liquid or gaseous is matter (water, air, etc.)
Since it can be liquid or gaseous it doesn't have to maintain it's shape and size to be matter.
The atom? gas? either one of those two would work
why must the bonds of these molecules be broken before anything else happens
Explanation:
yan po