The following text is from a science article about deep-sea exploration.
The Mariana Trench, the deepest part of the ocean, remained unexplored for most of human history. The crushing pressure at such depths—over 1,000 times atmospheric pressure—made early exploration impossible. Only with the development of specialized submersibles have scientists been able to observe the unique life forms that thrive in this extreme environment.
Which choice best describes the overall structure of the text?
It compares conditions in different ocean zones.
It describes a challenge, its cause, and how it was overcome.
It argues for increased funding for ocean research.
It profiles the scientists who explored the trench.
Correct Answer: B
Choice B is the best answer. The text identifies the challenge (unexplored trench), its cause (crushing pressure), and how it was overcome (specialized submersibles).
- Evidence: The text notes the trench "remained unexplored" (challenge) due to "crushing pressure" (cause). It concludes that "specialized submersibles" allowed observation (overcoming).
- Reasoning: The narrative arc is Problem -> Reason -> Solution.
- Conclusion: This matches "describes a challenge, its cause, and how it was overcome."
💡 Strategy: Identify the problem (can't explore) and the solution (new tech).
Choice A is incorrect because ocean zones aren't compared. Choice C is incorrect because no funding argument is made. Choice D is incorrect because no scientists are profiled.