Question

The job of the human heart is to circulate blood through all of the body's arteries, capillaries, and veins. The job of the human lungs is to supply the small amount of blood in them with oxygen. The interaction of these two parts of the human body results in a system that A. removes old blood from the body. B. circulates oxygen-filled blood throughout the body. C. turns the protein in blood into food energy for the digestive system. D. breaks down food energy, and turns it into heat.

Answer 1

B
All cells new oxygen and blood is a way for them to get it 

Answer 2

I say neither because the job of a humans lungs is to add new oxygen as well as taking out the old, but I would say A