Removal of wastes from metabolism and digestion is called what?

• A. Excretion
• B. Digestion
• C. Growth
• D. Hypertrophy

Answer: (A)

Excretion is the removal of wastes produced by metabolism and digestion from the body. These wastes include carbon dioxide from cellular respiration, urea from protein breakdown, excess water and salts, and other byproducts. The body uses multiple systems to excrete these wastes: the lungs release carbon dioxide during breathing, the kidneys filter the blood to form urine, the skin sweats to lose water and salts, and the liver helps process toxins that leave the body in feces. This is different from digestion, which is the breakdown of food into absorbable molecules, and from growth or hypertrophy, which involve increases in size rather than elimination of wastes.