Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer that best fits each of the numbered blanks.

The Great Barrier Reef is the earth’s largest reef system. At a length of over 2,500 km it is the ___(1)___ living structure. You can even see it from space. However, the reef is in danger of dying. Because of global ___(2)___, the temperature in the atmosphere keeps rising. This also affects the water temperature. When the oceans get too warm the colourful reefs ___(3)___ grey and die. The reef is also dying from pollution caused by factories on the Australian and Indonesian coasts.
It’s a pity that we don’t ___(4)___ the environment the ways the Aborigines did thousands of years ago. They respected nature, the animals and plants around them. They never killed more animals than they could eat. ___(5)___, when Europeans arrived in Australia they destroyed a lot of things that the Aborigines valued.