BIOLOGY > HUMAN BIOLOGY > CIRCULATORY SYSTEM
EXPLANATION:
The blood carries oxygen from the lungs to other parts of the body and carbon dioxide from the different parts of the body back to the lungs.
Shown in the image below is how the blood flows from the lungs to the heart and the rest of the body. The blue arrows represent the flow of oxygen-poor blood while the red arrows represent the flow of oxygen-rich blood.
ANSWER:
A: The blood that carries carbon dioxide is pumped by the heart to the lungs. The blood will get replenished with oxygen and the carbon dioxide is released to the lungs for exhalation.
B: The blood now carries oxygen and goes back to the heart.
C: The oxygen-rich blood will be pumped by the heart to the rest of the body. (High oxygen, no carbon dioxide)
D: The cells of the rest of the body produce carbon dioxide that will be exchanged in the blood for the oxygen it carries. The oxygen-poor blood will flow to the heart. (High carbon dioxide, no oxygen)
A-D cycle repeats indefinitely.