Correct Answer: C

Rationale: The tone of the essay is discouraged as it expresses concern about the U.S.'s lower life expectancy ranking and contributing factors.

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: D

Rationale: Onset in this context means commencement, referring to the beginning of dementia symptoms.

Correct Answer: B

Rationale: The word "duration" in the context of sleep refers to the length of time that children should sleep. It suggests a focus on the amount of sleep necessary for healthy development, making option B the correct choice as it aligns with the emphasis on recommended sleep hours for children.

Correct Answer: C

Rationale: The tone of the essay is discouraged as it expresses concern about the U.S.'s lower life expectancy ranking and contributing factors.