Which component of the blood is part of the body's immune system?

A.

plasma

B.

platelets

C.

red blood cells

D.

white blood cells

Answer: Plasma.

Explanation: Plasma is the liquid component of blood, in which the red blood cells, white blood cells, and platelets are suspended. It constitutes more than half of the blood's volume and consists mostly of water that contains dissolved salts (electrolytes) and proteins. The major protein in plasma is albumin.

A. Plasma