Correct Answer: A

Rationale: The author's purpose in discussing aquatic insects in relation to those that spend their entire lives in the air is to emphasize the adaptability and complexity of insect life cycles. The author highlights how some insects transition between aquatic and aerial environments, showcasing the diverse strategies and features these insects possess to thrive in different habitats. Choice B is incorrect because the author is not solely comparing aquatic insects with those that remain airborne, but rather exploring their adaptability. Choice C is incorrect as the focus is not on highlighting unique features but on showcasing the transition between environments. Choice D is incorrect as the author is not questioning the validity of studying insects in only one environment but rather demonstrating the fascinating dual-life cycles of certain insects.

Correct Answer: A

Rationale: The author's purpose in discussing aquatic insects in relation to those that spend their entire lives in the air is to emphasize the adaptability and complexity of insect life cycles. The author highlights how some insects transition between aquatic and aerial environments, showcasing the diverse strategies and features these insects possess to thrive in different habitats. Choice B is incorrect because the author is not solely comparing aquatic insects with those that remain airborne, but rather exploring their adaptability. Choice C is incorrect as the focus is not on highlighting unique features but on showcasing the transition between environments. Choice D is incorrect as the author is not questioning the validity of studying insects in only one environment but rather demonstrating the fascinating dual-life cycles of certain insects.

Correct Answer: C

Rationale: The sentence indicates that the insects undergo different stages of development, with the preparatory instars being aquatic and the adult instar being aerial. This highlights the adaptability of these insects to different environments. Choice A is incorrect as it focuses on the volume of water and air rather than the stages of development in different environments. Choice B is unrelated to the content of the sentence and does not capture the meaning accurately. Choice D is incorrect as it specifically mentions breathing through gills, which is not explicitly stated in the sentence. Therefore, choice C is the best interpretation of the sentence.

Correct Answer: D

Rationale: The correct answer is D. The speaker's final comment indicates a determination to keep looking for Hyde, as he expresses his intention to become 'Mr. Seek' if the other person is indeed 'Mr. Hyde.' This shows that the speaker is persistent in his search for Hyde, as he believes that discovering Hyde's identity could potentially unravel the mystery and clarify his friend's strange behavior. Choices A, B, and C are incorrect because the final comment does not imply a name change, an identity crisis, or a mistaken search but rather a firm decision to continue seeking out Hyde.

Correct Answer: A

Rationale: The spiracles in insects serve the crucial function of allowing them to breathe atmospheric air even when submerged. The passage explains that insects have a system of branching air-tubes that carry atmospheric air with oxygen to all tissues. The air enters these tubes through paired air-holes or spiracles, enabling insects to respire even when they are underwater. Choices B, C, and D are incorrect because the spiracles do not protect internal organs from water pressure, filter oxygen from water for underwater breathing, or expel carbon dioxide from the body. The primary role of spiracles is to facilitate respiration by allowing insects to access atmospheric air.