If a blood vessel is damaged, chemicals begin a chain reaction that causes platelets to stick to the vessel wall. The platelets release more chemicals that accelerate the clotting process. This process ends once the vessel wall has been repaired by a clot. this is an example of what?

A. a positive feedback loop

B. a negative feedback loop

C. thermoregulation

D. osmosis

What is a difference between systemic and pulmonary circulation? a. systemic circulation carries oxygenated blood to the lungs and pulmonary circulation carries deoxygenated blood to the body. b. systemic circulation carries deoxygenated blood to the lungs and pulmonary circulation carries oxygenated blood to the body. c. systemic circulation carries deoxygenated blood to the body and pulmonary circulation carries oxygenated blood to the lungs. d. systemic circulation carries oxygenated blood to the body and pulmonary circulation carries deoxygenated blood to the lungs.