Section: Paragraph Comprehension

30) The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching over 1,400 miles. The reef is located in the Coral Sea, off the coast of Queensland, Australia. It is the world's biggest single structure made by living organisms, is larger than the Great Wall of China and the only living thing on earth visible from space. This reef structure is composed of and built by billions of tiny organisms, known as coral polyps. Climate change, pollution and fishing are the primary threats to the health of this reef system. Other threats include shipping accidents, oil spills, and tropical cyclones. The Great Barrier Reef lost more than half of its corals since 1985, and two-thirds of the loss occurred since 1998 due to the factors aforementioned.

The three most impactful threats to the Great Barrier Reef are

1. oil spills, ship wrecks and hurricanes.
2. surfing, inappropriate fishing practices and snorkeling.
3. hurricanes, pollution and scuba diving.
4. climate change, pollution and inappropriate fishing practices.

The correct answer is choice (D). You are looking for the “most impactful”, mentioned in the passage as “primary”, threats to the Great Barrier Reef. This is a detail question so you can scan the paragraph to find the correct answer. You know it is most likely a detail question because it does not ask you to state the “main idea”, “best describe” or “infer”.