(blood serum is made of the substance ...) an antibody in blood serum that attaches to invading microorganisms and other antigens to make them more susceptible to the action of phagocytes
(... is made of the substance blood serum) the fluid (red in vertebrates) that is pumped through the body by the heart and contains plasma, blood cells, and platelets
"blood carries oxygen and nutrients to the tissues and carries away waste products""the ancients believed that blood was the seat of the emotions"