The Great Barrier Reef is the result of millions of years of continental (大陆的) shifts, sea-level changes, and layers of coral (珊瑚) growth. The Reef was built over millennia (数千年) by coral attaching itself to existing dead coral, as it continued to reach toward the light. Like most living things, coral needs the sun to survive and generally lives in shallow waters, where enough sunlight can penetrate (穿透) the water. Sea levels began to rise at the end of the last most recent ice age, about 14,000 years ago. As a result, the previously exposed Reef was covered by water and the coral expanded along the length of the newly revived Reef.

Climate change is having a dangerous impact on this natural wonder. Although coral and algae (海藻) have evolved despite climate change, allowing them to survive, coral has begun producing products that are poisonous to the Reef and block the growth of algae. Additional concerns include the overwhelming amount of pollution and chemical runoff into the water which harms the already affected coral and reduces biodiversity.

The Great Barrier Reef is well known as one of the best diving destinations in the world. You can do your part to help scientists preserve the Reef’s ecosystem while visiting. By paying a visit to the Reef, visitors pay a reef tax that will be used for the management and conservation of the Reef. A lesser-known contribution visitors can make to Reef preservation is signing up for REEFSearch. After signing up, you’ll be sent a field guide that will teach you how to collect information that scientists can use to study the Reef’ s health. During each dive, using the information sent to you, you will look for key species, check for coral conditions, and make note of any garbage found near the Reef. These small contributions can ultimately have a large impact and save one of the great wonders of the world.

【小题1】Why does coral live in shallow waters?

A．It must coexist with algae.	B．It needs sufficient sunlight.
C．It has to stick to dead ancestors.	D．It has to avoid deep-sea pollution.

【小题2】What drove the coral to stretch across the new Reef?

A．The rise of sea levels.	B．The exposure of it to air.
C．The change of its habitat.	D．The threat from its enemies.

【小题3】What is an impact climate change has on the Reef?

A．Coral cannot survive.	B．Algae become harmful.
C．Algae cannot be seen on the surface.	D．Coral produces something poisonous to the Reef.

【小题4】Which of the following should you do after signing up for REEFSearch?

A．Study the Reef’ s formation.	B．Find new habitats for coral.
C．Gather information on the Reef’ s health.	D．Search for dangerous species around coral.