Correct Answer: C

Rationale: The correct answer is C, osmotic pressure. Osmotic pressure within the body equalizes the solute concentration of ICFs and ECFs by shifting small amounts of water in the direction of higher concentration solute. Semipermeable membranes separate one fluid compartment from another and do not directly equalize solute concentrations. Hydration and perspiration are important elements of fluid balance but do not directly achieve the equalization of solute concentrations between ICFs and ECFs, which is primarily regulated by osmotic pressure.

Correct Answer: D

Rationale: The correct answer is D: Potassium. Chronic potassium deficiency can lead to hypertension, heart attack, stroke, kidney stones, and osteoporosis. Patients experiencing this deficiency may feel tired, weak, and irritable without knowing the cause.
Choice A (Zinc) is incorrect as zinc deficiency presents with different symptoms.
Choice B (Iron) deficiency is associated with anemia symptoms, not the conditions listed.
Choice C (Sodium) deficiency typically manifests as muscle cramps, weakness, and confusion, not the conditions described in the question.

Correct Answer: C

Rationale: The correct answer is C. Maintenance of more than 200 genes is not a function of vitamin A; instead, it is a function of Vitamin D. Vitamin A plays a crucial role in the prevention of night blindness by aiding in the production of the visual pigment rhodopsin. It also supports the growth of soft tissues and bone, as well as the integrity of body openings and their linings.
Choice C is incorrect because the maintenance of genes is primarily associated with Vitamin D, not Vitamin A.

Correct Answer: A

Rationale: The principal cation in plasma and interstitial fluid is sodium. Sodium plays a crucial role in maintaining fluid balance and is the primary cation in extracellular fluids like plasma and interstitial fluid. Potassium is the primary cation within cells, not in extracellular fluids, making it an incorrect choice. Calcium and magnesium are essential minerals but are not the principal cations in plasma and interstitial fluid, so they are also incorrect choices.

Correct Answer: C

Rationale: The correct answer is C. DRIs do not specifically address individuals with disease states; they are intended for the general healthy population.
Choice A is correct because DRIs indeed replace the older recommended daily allowances.
Choice B is correct as current DRIs aim to estimate required nutrients to enhance long-term health.
Choice D is accurate as DRIs also attempt to establish maximum safe levels of tolerance for nutrients.