Giải đề luyện giữa học kì II Tiếng Anh 9 — 14 câu tuyển chọn

The Great Barrier Reef lies in the Pacific Ocean off the north-eastern coast of Australia. Covering about 344,400 square kilometres, it is the world’s largest coral reef system. The reef is built by tiny living organisms called coral polyps and provides a home for an enormous variety of marine life. It is threatened by pollution, climate change and overfishing. When sea temperatures remain unusually high, coral can lose the algae that give it colour and energy. This process, called bleaching, can eventually kill the coral.