Correct Answer: B

Rationale: The correct answer is B. Water-soluble vitamins do not develop deficiencies rapidly because the body does not store them for long periods. They must be obtained through food constantly. Choice A is correct because water-soluble vitamins often act as coenzymes in various metabolic reactions. Choice C is correct as daily intake of water-soluble vitamins is necessary since they are not stored in the body. Choice D is incorrect as water-soluble vitamins are absorbed primarily in the small intestine, particularly in the duodenum and ileum, not the jejunum.

Correct Answer: C

Rationale: The correct answer is C: Secondary deficiency. A nutritional deficiency resulting from decreased intake is called a primary deficiency. On the other hand, a secondary deficiency refers to a vitamin deficiency caused by inadequate absorption or use, increased requirements, excretion, or destruction. Choice A, 'Unmeasurable,' is incorrect as it does not describe a type of nutritional deficiency. Choice B, 'Primary deficiency,' is incorrect as it refers to a deficiency caused by decreased intake, not inadequate absorption. Choice D, 'Codependent,' is incorrect as it is unrelated to the context of nutritional deficiencies.

Correct Answer: A

Rationale: Wernicke-Korsakoff syndrome is indeed associated with thiamine (vitamin B1) deficiency. This syndrome is commonly seen in individuals with chronic alcoholism due to poor diet and impaired thiamine absorption. Thiamine is essential for normal brain function and energy metabolism. Riboflavin (B2) deficiency can lead to symptoms like sore throat and swollen mucous membranes, not Wernicke-Korsakoff syndrome. Niacin (B3) deficiency causes pellagra, characterized by dermatitis, diarrhea, dementia, and death, but not Wernicke-Korsakoff syndrome. Pyridoxine (B6) deficiency can result in dermatitis, glossitis, and peripheral neuropathy, but it is not associated with Wernicke-Korsakoff syndrome.

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: 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.