Correct Answer: C

Rationale: The recommended fat intake is between 20% to 35% of total daily calories. This range is considered optimal for maintaining a healthy diet. Choice A (10% to 15%) is too low and might not provide enough essential fats for the body. Choice B (10% to 35%) includes an upper limit that exceeds the generally accepted range. Choice D (40% to 55%) suggests a fat intake that is higher than what is recommended, which could lead to health issues if consumed regularly.

Correct Answer: C

Rationale: The correct answer is C: 'Appropriate amounts of food from each food group.' MyPlate food guidance focuses on portion sizes from different food groups to promote a balanced diet. Choices A, B, and D are incorrect because MyPlate emphasizes the consumption of a variety of foods from different food groups rather than focusing solely on macronutrient percentages, exchange lists, or specific nutrient amounts.

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: A

Rationale: Individuals with optimal nutritional status differ from those with marginal nutritional status in their nutrient reserves. Optimal nutritional status implies having adequate nutrient reserves, which is lacking in marginal status. Clinical signs (choice B) may or may not be present in both groups and are not the differentiating factor between optimal and marginal statuses. Body weight (choice C) can vary for reasons other than nutritional status. The risk of mental illness (choice D) is not directly related to the comparison between optimal and marginal nutritional status.

Correct Answer: B

Rationale: A variety of foods is the best source of nutrients because it ensures a balanced intake of all essential nutrients required by the body. Option A, specific food combinations, may not provide all necessary nutrients as relying on only a few types of food may lead to deficiencies. Option C, individual foods, also may not provide a complete range of nutrients necessary for overall health. Option D, a variety of food supplements, is not the best source of nutrients as whole foods are generally more beneficial due to their natural nutrient composition and bioavailability.