Correct Answer: C

Rationale: The correct answer is C: Decline in kidney function. As people age, their kidneys may not work as effectively in conserving water and concentrating urine, leading to a higher risk of dehydration. Choice A is incorrect because more insensible losses do not directly relate to an increased risk of dehydration in the elderly. Choice B, an increase in muscle mass, is not a factor that leads to dehydration. Choice D, a decrease in fat, is also not a direct factor contributing to dehydration in the elderly.

Correct Answer: A

Rationale: The correct answer is A: live and can cause infection. Patients who are immunocompromised, like those receiving long-term steroids after an organ transplant, should not receive live vaccines because the live attenuated organisms in these vaccines can cause infections in individuals with weakened immune systems. Choice B is incorrect because attenuated vaccines are live but weakened, not mutated. Choice C is incorrect because while inactive, attenuated vaccines are not infectious. Choice D is incorrect because attenuated vaccines are not pathogenic; they are attenuated (weakened) forms of the pathogen.

Correct Answer: B

Rationale: Dehydration is more likely to occur in a 50-year-old man who is morbidly obese due to the increased risk of conditions like diabetes and heart disease that can lead to fluid imbalances. Being morbidly obese can also strain the body's systems, increasing the need for water. The other choices are less likely to experience dehydration as a primary concern. While being a bodybuilder may require strict hydration practices, dehydration is more prevalent in individuals with conditions like obesity.

Correct Answer: A

Rationale: Truncal obesity with thin extremities is a classic manifestation of Cushing syndrome due to the redistribution of fat. Enlargement of face, hands, and feet is seen in conditions like acromegaly, not Cushing syndrome. Cachexia is a state of severe weight loss and muscle wasting, typically seen in conditions like cancer or advanced infections. Thick scalp hair is not typically associated with Cushing syndrome.

Correct Answer: C

Rationale: The correct answer is 'genetically modified food.' Canola oil derived from genetically modified canola plants falls into this category because the plant's genome has been altered to exhibit herbicide resistance. This genetic modification makes it a genetically modified food. Choice A, 'pesticide-free food,' is incorrect as the genetic modification is to resist herbicides, not pesticides. Choice B, 'saturated fat food,' is incorrect as it does not accurately describe the genetic modification of the canola plants. Choice D, 'product that is pure,' is too vague and does not address the genetic modification aspect of the canola plants.