C
Conservationists have made plans to preserve and protect the world's most important species of coral, in a response to increasing threats that they say will lead to "functional extinction" within decades．
Led by scientists at the Zoological Society of London, the Edge Coral Reefs project has identified 10 coral species in most urgent risk of becoming extinct．The scientists say that reefs are under pressure from a variety of threats including rising sea temperatures due to climatic instability, increased acidity（酸性）, overfishing and pollution．
The Edge plan, which focuses on the most evolutionarily distinct and globally endangered species , will take a regional approach to conservation．This means focusing on the "coral triangle" around the Philippines, the West Indian Ocean around the Mozambique channel, and in the Caribbean channel．
"Coral reefs are threatened with functional extinction in the next 20-50 years, due predominantly to global climatic instability," said Catherine Head, coordinator of the reefs project．"In these regions, we'll be supporting and training in-country conservationists to carry out research and implement targeted conservation actions," she said．"Their projects will last for two years．We provide them with a whole host of tools to carry out their projects including funding and intensive training．" She added．
Coral reefs are the planet's most diverse marine ecosystem, known as the rainforests of the oceans．Despite taking up under 0．2% of the ocean floor, they provide food and shelter for almost a third of all sea life．If we lose the ecosystems, we lose not only the biodiversity, but we also lose the capability of people to obtain income and food from coral reefs．
Climatic instability, which leads to rising sea temperatures, causes corals to bleach(漂白)．Bleaching occurs when sea temperatures rise and this causes the coral tissue to expel their symbiotic algae called zooxanthellae - these are what give the coral their color．Bleached corals often die if the stress continues．Among the 10 species chosen to start the Edge project are the pearl bubble coral, a food source for the hawksbill turtle, and the Mushroom coral, which supports at least 15 brightly colored fish．
What have conservationists done to react to the increasing threats to corals?

A．They have taken measures to preserve and protect corals.

B．They are doing research into sea life.

C．They have identified some endangered corals worldwide.

D．They have prevented people from going to some areas.

Which is NOT the reason for the extinction of corals?

A．Rising sea temperature．	B．Human exploration．
C．Pollution．	D．Overfishing．

According to the passage, coral reefs________.

A．are known as the rainforests on the earth．

B．are threatened with functional extinction in the following 10 years．

C．takes up 2% of the ocean floor．

D．are the planet's most diverse marine ecosystem．

The coral extinction will ________.

A．help to keep the balance of the marine ecosystems

B．have no effect on the human life

C．cause the loss of one third of the marine life

D．destroy the rainforests on our earth．

What does the writer mainly talk about in the passage?[

A．Climatic instability and coral extinction．

B．A plan to protect coral from extinction．

C．Reasons for coral functional extinction．

D．A research about endangered coral reefs．