The professional primarily responsible for the application of nutrition science in clinical practice settings is the:

Correct Answer: D

Rationale: The correct answer is D: registered dietitian. A registered dietitian is a healthcare professional with specialized training in nutrition and dietetics, making them primarily responsible for applying nutrition science in clinical practice settings. Nurses (choice A) and physicians (choice B) may have some knowledge of nutrition, but a registered dietitian has specific expertise in this area. Public health nutritionists (choice C) typically focus on community nutrition and public health programs, rather than clinical practice settings.

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.

Correct Answer: B

Rationale: Proteins are indeed macronutrients, along with carbohydrates and fats. Macronutrients are nutrients that provide energy and are required in large amounts by the body. Minerals and vitamins are considered micronutrients, as they are needed in smaller quantities. Enzymes, on the other hand, are not nutrients but rather biological molecules that act as catalysts in biochemical reactions.

Correct Answer: C

Rationale: Micronutrients are essential nutrients needed by the body in small quantities to support various bodily functions. Vitamins fall under this category as they play crucial roles in metabolism, immune function, and overall health. While fats, proteins, and carbohydrates are essential macronutrients required in larger amounts for energy and growth, they are not classified as micronutrients. Therefore, the correct answer is C.

Correct Answer: A

Rationale: The correct answer is A: provide energy. Nutrients play a crucial role in providing energy for the body's various functions. While they do help in regulating metabolic processes and in building and repairing tissue, the primary function related to energy production. Choices B, C, and D are incorrect as nutrients are not primarily responsible for controlling cellular wastes, hormone levels, or absorption.