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: Low income is a significant factor contributing to marginal nutritional status due to limited access to nutritious food. While dependence on caffeine or acute illness can impact health, they are not as directly linked to marginal nutrition as low income. The size of the family unit may affect food distribution within the household but is not as directly related to marginal nutritional status as low income.

Correct Answer: B

Rationale: The correct answer is 'B: amino.' Amino acids are the fundamental units that make up proteins. They are essential for various bodily functions, including building and repairing tissues. Choice A, 'fatty acids,' are not the basic building blocks of proteins but rather a type of lipid. Choice C, 'nucleic acids,' are the building blocks of nucleic acids like DNA and RNA, not proteins. Choice D, 'omega fatty acids,' are a specific type of fatty acid known for their health benefits but are not directly related to the building blocks of proteins.

Correct Answer: A

Rationale: The correct answer is A: serosa. The serosa is the outermost layer of the intestinal wall, providing a protective covering. Choice B, mucosa, is the innermost layer responsible for absorption. Choice C, submucosa, lies beneath the mucosa and contains blood vessels and nerves. Choice D, muscularis mucosae, is a smooth muscle layer located within the mucosa, helping to create folds in the intestinal lining to increase surface area for absorption.

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.