Correct Answer: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 is primarily found in animal products, so individuals following a vegan diet are at risk of deficiency as they do not consume these sources. Vitamin C, Carbohydrates, and Fiber are not specifically at risk for deficiency in vegan diets as they can be obtained from plant-based sources.

Correct Answer: D

Rationale: The correct answer is D, conducting nutrition assessments. Registered dietitians are responsible for assessing an individual's nutritional status, dietary intake, and health needs. This assessment forms the basis for developing personalized nutrition care plans. Choices A and B involve the administration of specialized nutrition support, which is typically done by healthcare providers with specific training in those areas. Choice C, prescribing diet orders, may fall outside the scope of practice for a dietitian as they focus more on assessment, education, and counseling related to nutrition rather than prescribing medical treatments.

Correct Answer: D

Rationale: Osmotic pressure is the force that drives water movement across cell membranes due to the presence of electrolytes, helping to balance fluid levels in the body. Choice A, 'energy,' is incorrect as electrolytes do not directly create energy. Choice B, 'active transport,' refers to the movement of molecules across a cell membrane requiring energy, not the movement of water. Choice C, 'passive diffusion,' is the process by which substances move from an area of higher concentration to lower concentration, not related to the movement of water following electrolytes.

Correct Answer: D

Rationale: The correct answer is 'none of the above.' Human digestive enzymes like salivary amylase and pancreatic amylase cannot digest fiber. Instead, fiber is fermented by gut bacteria in the large intestine. Cellulase, which is an enzyme produced by some animals and microorganisms, can break down cellulose found in plants, but it is not a human digestive enzyme, making it an incorrect choice in this context.

Correct Answer: B

Rationale: Individuals with lactose intolerance lack the enzyme lactase needed to break down lactose. Milk contains lactose, a sugar found in dairy products, and should be avoided by individuals with lactose intolerance. Choices A, C, and D are not sources of lactose and are generally well-tolerated by individuals with lactose intolerance.