The body gains water by absorbing water form the slurry in the lumen of the small intestine and from (1) ______ during condensation reactions. The mammalian body loses water mostly by excretion of (2) ____, evaporation through the skin and (3) ____, elimination of feces from the gut, and (4) _____ as the body is cooled. (5) ____ behavior, in which the brain compels the individual to seek liquids, influences the gain of water. The body gains solutes by absorption of substances from the gut, by the secretion of hormones and other substances, and by (6) _______, which produces carbon dioxide and other waste products of degradative reactions. Besides carbon dioxide, there are several other metabolic wastes that must be eliminated: (7) _______, formed when amino groups are detached from amino acids; (8) _____, which is produced in the liver during reactions that link two ammonia molecules to carbon dioxide and release a molecule of water, and (9) ____ _____, which is formed in reactions that break down nucleic acids. a. uric acid b. lungs c. sweating d. thirst e. urea f. ammonia g. metabolism h. urin
