I think it is repeatable, testable, observable
The answer is it provides us with vitamins. Hope this helps.
Heart Blood vessels. (Arteries, Capillaries, and Veins)
The answer is sex cells or gametes
Carbon dioxide in the tissues is produced as the result of oxidation of glucose...
This carbon dioxide in process of respiration diffuse out of the tissues in form of molecular carbon dioxide and join with water forming carbonic acid ...
In lungs again carbon dioxide is separated and released out of the body...
