Correct Answer: A

Rationale: The correct answer is A: Glycogen. Glycogen is the stored form of carbohydrates in the body, primarily found in the liver and muscles. Starch (choice B) is a carbohydrate storage molecule in plants, not in the human body. Fat (choice C) is a different macronutrient and not the main storage form of carbohydrates. Glucose (choice D) is a simple sugar that serves as an energy source, not the main storage form of carbohydrates.

Correct Answer: B

Rationale: The correct answer is B: 'fulfill specific metabolic roles.' Nutrients play essential roles in specific metabolic processes in the body such as energy production, tissue repair, and growth. Choice A, 'work independently,' is incorrect as nutrients often work synergistically rather than alone. Choice C, 'influence weight loss,' is incorrect as while some nutrients may support weight loss indirectly through metabolic processes, it is not their primary characteristic. Choice D, 'improve mental status,' is also incorrect as while some nutrients are important for brain health, their primary role is not specifically to improve mental status.

Correct Answer: D

Rationale: The correct answer is D: 45% to 65%. Carbohydrates should contribute between 45% to 65% of the total daily caloric intake for healthy individuals to maintain a balanced diet. Choices A, B, and C are incorrect because they suggest lower ranges, which may not provide sufficient energy from carbohydrates for overall health and well-being.

Correct Answer: C

Rationale: Public health nutritionists work within communities to ensure that populations have access to nutritional resources. They focus on promoting good nutrition, developing programs, and educating the public about healthy eating habits. While community physicians, public health nurses, and registered dietitians may also play roles in promoting nutrition in the community, the primary responsibility for nutrition care typically falls under the purview of public health nutritionists.

Correct Answer: A

Rationale: Carbohydrates are the body's primary source of energy. When carbohydrates are consumed, they are broken down into glucose, which is used by the body's cells for energy production. Fats and proteins are also essential nutrients, but carbohydrates are the preferred energy source for the body due to their quick conversion into fuel. Vitamins are not a direct source of energy but play crucial roles in various bodily functions.