Correct Answer: D

Rationale: Generalized weakness is a key indicator of malnutrition and is often assessed as part of functional status, reflecting muscle wasting and reduced physical function. The other choices, such as severity of illness, presence of pressure sores, and localized edema, are important factors to consider in a clinical assessment but are not primarily indicative of malnutrition risk. Generalized weakness directly relates to the functional impact of malnutrition on physical performance.

Correct Answer: B

Rationale: The correct answer is B: '21%'. Approximately 21% of persons in the United States who have HIV infection are unaware that they are infected. This percentage represents a significant portion of individuals who are not aware of their HIV status, highlighting the importance of increased testing and awareness campaigns. Choices A, C, and D are incorrect as they do not align with the estimated percentage provided in the context.

Correct Answer: C

Rationale: The correct answer is C, Larynx. The larynx is part of the respiratory system, responsible for voice production and breathing. The alimentary canal is involved in the digestive process and includes structures like the oral cavity (mouth), pharynx, and esophagus. Choices A, B, and D are parts of the alimentary canal, where digestion occurs, making them incorrect answers.

Correct Answer: C

Rationale: The correct answer is Vitamin B3, also known as Niacin. Niacin is essential for energy metabolism and can help improve cholesterol levels. Vitamin B1 is Thiamine, Vitamin B2 is Riboflavin, and Vitamin B12 is Cobalamin. These vitamins have different functions in the body and are not synonymous with Niacin.

Correct Answer: B

Rationale: Reduced stomach acidity impairs the absorption of iron, as an acidic environment is necessary for optimal iron absorption in the stomach. Choices A, C, and D are incorrect as medications that reduce stomach acidity typically do not significantly affect the absorption of calcium, vitamin D, or vitamin C.