The correct answer is A. respiratory and circulatory. These two systems work together in the process of gas exchange and transporting oxygenated blood from the lungs to the heart.
Multiple Choice Question
Oxygen-rich blood returns from the lungs to the heart. Which two systems are most directly involved in this process?
A.
respiratory and circulatory
B.
excretory and digestive
C.
circulatory and excretory
D.
digestive and respiratory
1 answer