Nutrients interact in the body to regulate metabolic processes, build and repair tissue, and to:

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.

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.

Correct Answer: C

Rationale: The primary function of carbohydrates as a food source is to supply energy. Carbohydrates are the body's main source of energy, providing fuel for various physiological functions. Choice A is incorrect because carbohydrates do not primarily regulate metabolic processes; that role is mainly attributed to enzymes and hormones. Choice B is incorrect because proteins are primarily responsible for building body tissue. Choice D is incorrect because fiber, not all carbohydrates, provides bulk in the diet.

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: 120. Carbohydrates provide 4 kcal per gram, so 30 grams of carbohydrates will provide 120 kcal. This is calculated by multiplying the grams of carbohydrate (30) by the kcal per gram (4). Choices A, C, and D are incorrect because they do not reflect the correct calculation based on the energy content of carbohydrates.