Reading Comprehension

Read the following passage and answer the question below. Coral reefs, often called the rainforests of the sea, are among the most biologically diverse ecosystems on Earth, despite covering less than one percent of the ocean floor. These structures are built by tiny organisms called coral polyps, which secrete calcium carbonate to form hard skeletons that accumulate over thousands of years. Reefs provide habitat and shelter for approximately a quarter of all marine species, making them essential to ocean biodiversity. Unfortunately, coral reefs are highly sensitive to changes in water temperature, and rising sea temperatures caused by climate change have led to widespread coral bleaching, a process in which corals expel the algae living in their tissues and turn white. Prolonged bleaching can lead to coral death, threatening the entire ecosystem that depends on the reef. Conservationists are now working on methods such as coral farming to help restore damaged reefs around the world. Question: According to the passage, approximately what proportion of marine species rely on coral reefs for habitat?

• A. Approximately a half
• B. Approximately a tenth
• C. Approximately all marine species
• D. Approximately a quarter ✓