Correct Answer: A

Rationale: In this context, 'lethargy' refers to a state of sluggishness or lack of energy. The passage mentions that people with seasonal affective disorder (SAD) struggle with lethargy and chronic fatigue, impairing their daily lives. Therefore, the correct definition of 'lethargy' in this context is 'sluggishness.' Choice B, 'Irritability,' is incorrect as lethargy refers more to a lack of energy than to being irritable. Choice C, 'Energy,' is the opposite of lethargy. Choice D, 'Starvation,' is unrelated to the definition of lethargy in this context.

Correct Answer: D

Rationale: The main idea of the passage is that lack of adequate sleep is becoming a major national health problem.

Correct Answer: A

Rationale: The correct answer is A. The passage mentions a previous study by the same team on the connection between exercise and energy, indicating that the lab had conducted such research before. Choice B is incorrect because the passage actually states that low-impact exercise can help reduce fatigue in patients with serious health conditions. Choice C is incorrect as the passage indicates that an increase in energy levels does correspond to a reduction in fatigue. Choice D is incorrect as the passage does not provide information on the exact number of participants in each group.

Correct Answer: D

Rationale: The correct answer is D. While the passage extensively discusses the benefits and applications of phototherapy, it does not mention that ultraviolet rays can cause damage to eyes and skin. This statement goes beyond the information provided in the passage and cannot be inferred. A. The passage mentions that phototherapy has been around for more than a century, supporting the statement that some forms of phototherapy have been around for decades. B. The passage discusses how new applications of phototherapy, like the phototherapy blanket, are being developed, making this statement valid as it aligns with the information provided. C. Phototherapy being most often used to treat skin problems is supported by the passage, which mentions its applications in treating acne, psoriasis, and eczema. Therefore, this statement can be inferred from the passage.

Correct Answer: A

Rationale: In this context, 'integral' means 'central' or essential. The passage discusses the debate around spanking as a method of discipline. Some parents consider it an integral part of teaching right and wrong, highlighting its central importance. Therefore, the correct answer is 'A: Central.' Choice B, 'Initial,' is incorrect as the word 'integral' does not refer to something being at the beginning of a process or sequence. Choice C, 'Trifling,' is incorrect as 'integral' implies significance and importance, opposite to being trivial. Choice D, 'Irrelevant,' is incorrect as the passage clearly states that some parents view spanking as essential, making it relevant and not irrelevant.