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: What is coral bleaching, according to the passage?
- A. A type of ocean current
- B. A process where corals expel algae and turn white ✓
- C. A disease that only affects fish
- D. A method of farming coral
Correct answer
B. A process where corals expel algae and turn white
Explanation
The passage defines coral bleaching as the process in which corals expel the algae in their tissues and turn white.