Which of these is a function of the circulatory system?

a. removing waste from tissues

b. delivering carbon dioxide to cells for cellular respiration

c. transferring impulses from one cell to another

d. all of the above

The correct answer is letter A: the circulatory system removes waste from the tissues by converting carbon dioxide-rich blood into oxygen-rich blood that can be circulated throughout the body to support its several functions. Without the lungs the human body will not be able to process converting blood cells into oxygen-rich cells in the body.