Final answer:
The principal blood reservoirs of the body include the liver, skin, and spleen.
Step-by-step explanation:
The principal blood reservoirs of the body include the liver, skin, and spleen.
The liver filters the blood and removes damaged or defective red blood cells. The skin helps maintain an environment free of microorganisms in the blood. The spleen filters and stores blood, removes damaged red blood cells, and is a reservoir for immune factors.