Correct Answer: A

Rationale: One tablespoon of peanut butter is equivalent to one serving from the Protein group in MyPlate. It provides a good amount of protein and healthy fats. Choices B, C, and D are incorrect as they represent larger serving sizes than a single serving from the Protein group in MyPlate. 3 oz of fish, 2 oz of cheese, and 1/2 cup of cooked dry beans or peas would exceed the recommended serving size for the Protein group.

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: B

Rationale: Peristalsis is the correct answer because it refers to the rhythmic contractions that propel food through the intestinal tract by pushing it along the digestive system. Segmentation, on the other hand, refers to the mixing movements in the intestines rather than the forward movement of food. Cardiospasm is a condition characterized by difficulty swallowing due to the inability of the esophagus to relax, and pendular movements are a type of motility found in the small intestine but do not specifically refer to the propulsion of food.

Correct Answer: A

Rationale: The correct answer is A: potassium and vitamin A. Vegetables are an excellent source of potassium and vitamin A, both essential for maintaining overall health. Iron and vitamin C (choice B) are commonly found in foods from the Protein and Fruits groups, respectively. Calcium and vitamin B12 (choice C) are more abundant in dairy products and animal-based foods. Sodium and vitamin E (choice D) are not the major nutrients typically supplied by vegetables.

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.