Answer: d
The respiratory and circulatory systems bring oxygen and nutrients to the cells. The respiratory and circulatory systems work together to maintain homeostasis. The respiratory system moves gases into and out of the blood. The lungs contain the bronchi, bronchioles, and alveoli.
Explanation:
C. that is your answer because as your heart contracts, blood flows and IF your heart is not strong enough, it will be hard to breathe.
Usually there is a big difference when it comes to the purpose of the medical research. For instance, with forensics, you are attempting to solve passed crimes with DNA found on scenes. However, with medical, you are using DNA to do things for the living, or to help people stay alive. This could range anywhere from organ donations to blood mutations.
I'm going to be a forensics major, so if you have any more questions, PM me!
Hope this helps! <3