Question

Which of the following provides the best evidence that the circulatory system and the respiratory system work together to carry out their functions?
A : Nutrients are absorbed into the blood from the intestines.
B : Lungs expand and contract through movements of the diaphragm.
C : New red blood cells are generated in the marrow of bones.
D : Gases exchanged in the lungs are carried by the blood.

Answer 1

Answer:

D

Explanation:

Your first order of business should always be to see which answers involve both of the systems. A has the circulatory system (blood) but no respiratory system (intestines are the gastrointestinal system), B has the respiratory system (the lungs) but no circulatory system, C has the circulatory system (new red blood cells) but not the respiratory system (bones are the skeleton), and that just leaves D, so it has to be the answer. When you look at it to check, it includes both systems, as the lungs are part of the respiratory system and the blood is part of the circulatory system.