Multiple choice

Which of the following facts about corals are true?

  1. Polyps, which make up corals, belong to the same group of animals as jellyfish.
  2. Coral reefs are also called ‘rainforests of the sea’.
  3. Coral reefs are home to a quarter of marine species.

  1. Both 1 and 2

  2. Both 2 and 3

  3. Both 1 and 3

  4. All three
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps belong to a group of animals known as Cnidaria, which also includes sea anenomes and jellyfish. Often called "rainforests of the sea", coral reefs form some of the most diverse ecosystems on Earth. They occupy less than 0.1% of the world's ocean surface, about half the area of France, yet they provide a home for 25% of all marine species including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians.

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