63. Which of the following statements about coral reef is not true? (A) Corals are a diverse group of cnidarians. (B) Corals can excrete external, carbonaceous skeletons. (C) Symbiotic dinoflagellate algae live in their tissue. (D) High water temperatures cause corals to ‘bleach’. (E) The problem of bleaching in corals at Kenting National Park is especially severe in winter months.