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: 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: B

Rationale: Energy drinks are known for causing a variety of health issues, including nervousness, seizures, and an increased risk of dental caries due to their high sugar content. However, they do not cause bradycardia, which is a slow heart rate. Instead, energy drinks are associated with causing an increased or rapid heart rate, known as tachycardia. Therefore, out of the listed options, bradycardia is the condition not caused by energy drinks.

Correct Answer: C

Rationale: Eggs are a safe food choice for individuals with celiac disease as they are naturally gluten-free. Scalloped potatoes often contain flour in the sauce, which might contain gluten. Oatmeal can be a subject of debate due to possible cross-contamination during processing, so it might not be safe unless labeled gluten-free. Tortillas are typically made from wheat flour containing gluten, but gluten-free versions are available. However, eggs are universally gluten-free, making them the best choice for individuals with celiac disease.

Correct Answer: B

Rationale: Active transport is the mechanism essential for the absorption of monosaccharides in the intestine. This process requires energy to move molecules against their concentration gradient, allowing for the absorption of monosaccharides efficiently. Phosphorylation, the process of adding a phosphate group to a molecule, is not directly involved in the absorption of monosaccharides. Passive diffusion, a process that does not require energy, is not the primary mechanism for absorbing monosaccharides due to their large size. Facilitated diffusion, a type of passive transport that involves carrier proteins, is not the primary mechanism for monosaccharide absorption, as monosaccharides require active transport for efficient absorption.