Correct Answer: C

Rationale: The passage lists important nutrients for seniors, including fiber, calcium, vitamin D, and B12, while exercise is also discussed as crucial for health. However, nitrates are not mentioned at all, making option C correct since it stands out as the only nutrient not discussed in the context of seniors' health

Correct Answer: C

Rationale: Weight loss is not mentioned as a side effect of NSAIDs in the passage.

Correct Answer: B

Rationale: The inference that can be made is that medical mistakes can happen even at the best hospitals.

Correct Answer: C

Rationale: The correct answer is C. The passage emphasizes the importance of certain bacteria for a properly functioning immune system. It discusses how harmless bacteria play a crucial role in defending the body against pathogens. Choice A is incorrect as it focuses on the immune system's response to certain types of bacteria in lower organisms, not the overall importance of bacteria for immunity. Choice B is incorrect as it mainly discusses bacteriotherapy in relation to the reconstruction of a damaged colon, rather than the broader role of bacteria in immune system health. Choice D is incorrect as it only talks about the process of replacing harmful bacteria with harmless ones, missing the key point about the necessity of certain bacteria for immune system function.

Correct Answer: D

Rationale: The passage discusses the dangers of medical errors and provides specific examples of such errors but does not indicate that overmedication is the most common error. Therefore, since option D is not supported by the text, it is the correct choice for what is not mentioned.