Metabolic acid-base disorders are compensated by the kidneys adjusting bicarbonate levels.

False: Aqueous secretions including saliva, gastric juice, and succus entericus are essential for the enzymatic hydrolysis of nutrients. Proper hydration ensures adequate production of these digestive fluids to facilitate motility and absorption. Dehydration leads to constipation and impaired nutrient uptake.

A. It blocks waste excretion pathways: Water is essential for the clearance of metabolic wastes through the renal and integumentary systems. It serves as the vehicle for excretion rather than a barrier. Dehydration, not water, leads to the accumulation of toxic metabolites in the bloodstream.

B. It stores energy for cellular metabolism: Adenosine triphosphate and glycogen are the molecules responsible for energy storage and transfer. Water is an inorganic molecule that does not contain high-energy phosphate bonds or caloric value. It facilitates the hydrolysis reactions that release energy from these molecules.

C. It builds structural proteins in tissues: Proteins are synthesized from amino acids via translation in the ribosomes. While the hydrophobic effect of water helps proteins fold into their functional shapes, water is not a building block of protein. It provides the medium in which these structures exist.

D. It dissolves solutes to facilitate biochemical reactions: The polar nature of water allows it to dissociate ionic compounds and surround polar molecules. This creates a homogeneous medium where reactants can collide and interact chemically. It is the fundamental solvent for all intracellular and extracellular metabolic pathways.