(1) Millions of people depend upon coral reefs for their livelihoods. (2) Small island countries with coral reefs rely on them to attractsightseers, scuba divers, snorkelers, and other tourists. (3) They are an important source of food for the people who live nearby. (4) Reefs inshore areas are shields from pounding waves, storm surges, and tsunamis. (5) Several important medical drugs for cancer research have beendeveloped from chemicals found there. (6) However, coral reefs are threatened by water pollution, oil spills, and pesticides. (7) Another threatto coral reefs is a steady increase in average temperatures around the Earth, called climate change or global warming. (8) Most scientiststhink that the warming is caused by the greenhouse effect, an increase of carbon dioxide and other heat-trapping gases in our atmosphere.(9) This causes ocean temperature to rise, and as a result, some coral reefs are dying. (10) Coral reefs are also injured or destroyed whenpeople mine the coral for building materials or break it to sell as souvenirs and jewelry. (11) Dangerous fishing practices, such as fishing byusing explosives, also harm reefs.
【題組】40.What is the main message of the passage?
(A) How coral reefs form and why they are in danger.
(B) What people get from coral reefs and why corals are in danger.
(C) Where people discover coral reefs and why they are in danger.
(D) How different kinds of coral reefs are used and why they are contaminated.