Correct Answer: D

Rationale: The correct answer is D. The stomach is protected from gastric acid by a thick mucus lining that acts as a physical barrier, preventing the acid from eroding the stomach walls. Enzymes in the stomach help with digestion but do not play a significant role in protecting the stomach from acid damage, so choice A is incorrect. While some bacteria in the stomach can be beneficial, they do not primarily protect the stomach from gastric acid, making choice B incorrect. Bicarbonate, a base, can neutralize acid, but it is not the primary defense mechanism against gastric acid in the stomach, so choice C is also incorrect.

Correct Answer: A

Rationale: The correct answer is A: prebiotic. Fiber acts as a prebiotic by providing a food source for beneficial bacteria in the colon, promoting their growth and activity. This helps maintain a healthy balance of microflora in the gut. Choice B, probiotic, is incorrect as fiber itself does not contain live beneficial bacteria but rather supports their growth. Choice C, functional food, is too broad and doesn't specifically address fiber's role in promoting beneficial bacteria. Choice D, protective agent, is vague and does not directly relate to fiber's specific function in colon microflora.

Correct Answer: C

Rationale: According to the MyPlate guide, beans and peas are classified as part of both the protein and vegetable groups due to their high protein content and the nutrients they share with vegetables. This makes Choice C correct. Choice A is incorrect as canned fruit can be part of the fruit group if it's canned in water or 100% fruit juice. Soymilk is considered part of the dairy group, making Choice B incorrect. While cream cheese and butter are dairy products, they are not part of the dairy group on MyPlate because they contain little to no calcium, making Choice D incorrect.

Correct Answer: B

Rationale: It is false that the major determinant of a person's total cholesterol levels is the amount of cholesterol in their diet. While dietary cholesterol can have some impact on total cholesterol levels, it is not the major determinant. The amount and types of fats consumed, particularly saturated and trans fats, have a more significant impact on blood cholesterol levels. Therefore, a diet high in these types of fats can lead to high cholesterol, irrespective of the amount of dietary cholesterol consumed. This is why it is essential to maintain a balanced diet with a limited intake of saturated and trans fats.

Correct Answer: C

Rationale: The correct answer is vitamin E. Vitamin E is the major antioxidant found in cell membranes, where it plays a crucial role in protecting them from oxidative damage. Although B12, beta-carotene, and vitamin A are important nutrients with specific functions in the body, they are not the primary antioxidants found in cell membranes. Vitamin E specifically localizes in cell membranes to neutralize free radicals and prevent lipid peroxidation, making it an essential antioxidant for cellular health.