Correct Answer: D

Rationale: The Tolerable Upper Intake Level (UL) represents the highest amount of a nutrient that can be safely consumed without causing adverse health effects. It is not a replacement for Recommended Dietary Allowances (RDAs) (choice A) which are nutrient intake recommendations. While the UL is established to prevent toxicity, it is not a completely safe level for people of all ages (choice B). It is also not a potentially toxic level of intake of a nutrient (choice C), but rather the level that is unlikely to cause adverse health effects.

Correct Answer: C

Rationale: Dietary guidelines are designed to assist individuals in making smart food choices by providing recommendations on what to eat to maintain good health. While portion sizes may be a part of these guidelines, they are not the primary focus. Designing a personal food plan involves individual preferences and needs, which may go beyond general guidelines. Avoiding excessive nutrient intakes is important, but dietary guidelines aim to provide balanced recommendations rather than just focusing on avoiding excess.

Correct Answer: B

Rationale: The correct answer is B: nutrition science. Nutrition science specifically focuses on studying the requirements and functions of nutrients in relation to human growth, maintenance, activity, and reproduction. Choice A, physiology, deals more with the functions of living organisms and their parts, not specifically related to nutrients. Choice C, biochemistry, focuses on the chemical processes and substances that occur within living organisms, not specifically centered on nutritional requirements. Choice D, dietetics, involves the application of nutritional knowledge in planning and managing diets for individuals, but it is more focused on the practical aspect rather than the broader scientific study of nutritional requirements.

Correct Answer: A

Rationale: The correct answer is A: prevention and control of chronic diseases. In this century, nutritional recommendations have increasingly emphasized the importance of preventing and managing chronic diseases like obesity, diabetes, cardiovascular diseases, and cancer. Lifestyle factors such as diet play a significant role in the development of these conditions. Option B, improved sanitation and public health, although important for overall health, is not the primary focus of nutritional recommendations. Option C, prevention and control of infectious diseases, is also crucial but does not reflect the current major focus of nutritional recommendations. Option D, development of healthful foods using food technology, is a valid area of interest but is not the primary shift in focus observed in nutritional recommendations.

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.