Scientists around the world are looking for means to protect and maybe increase corals.One common option is to create more protected areas — essentially national parks in the ocean.Beyond nature preserves，some conservationists are looking to more hands-on methods.One research center in the Florida Keys is exploring a form of natural selection to keep corals remaining.The reef system in the Keys has been hit hard by climate change and pollution，which is especially tough，because corals there help support fisheries worth ＄100 million every year. To keep the wild ecosystem alive，Erinn Muller，the center's director，and her team are harvesting samples of the corals that survived the environmental stress naturally，keeping them to make them reproduce，and then reattaching them to the reef.They have 46，000 corals on plastic frames under the sea.So far，the center has regrown over 70，000 corals from five different species on damaged reefs. In The Bahamas，Ross Cunning，a research biologist at Chicago's Shedd Aquarium，focuses on corals with genes that could make them natural candidates for restoration projects.He published a study of two Bahamian reefs，one that survived an extreme 2015 heat wave，and one that didn't. "We think their ability to deal with these higher temperatures is built into their genes，" says Cunning.There's evidence of corals evolving more quickly to resist rapidly warming climate.The big question scientists need investigate，adds Cunning，is how much more heat corals can adapt to.（1）What does the underlined word "halt" in the first paragraph mean？ ____ A.End.B.Develop.C.Strengthen.D.Weaken.（2）What do Muller and her team do to save corals？ ____ A.Restore the damaged reefs.B.Grow corals by hand underwater.C.reate more protected areas.D.Move corals to unpolluted areas.（3）What do Cunning's words suggest？ ____ A.Many corals have been genetically improved.B.Cooling down the waters is key to rescuing corals.C.Reasons for corals surviving heat waves are shocking.D.The highest temperature corals can survive is unclear.（4）Which can be a suitable title for the text？ ____ A.Relationship between corals and algaeB.Efforts made to save coralsC.Impact of climate warming on coralsD.Survival crisis faced by coral reefs

Scientists often compare coral reefs（珊瑚礁）to underwater rainforests，yet unlike the leafy plant base of a forest，corals are animals.The soft creatures are naturally half-transparent and get their brilliant color from algae（藻类）living inside them.When corals experience stress from hot temperatures or pollution，they halt the interdependent relationship with algae，typically pushing them out and turning white.Corals are still alive when they are white，but they're at risk and many eventually die，turning dark brown.
    Scientists around the world are looking for means to protect and maybe increase corals.One common option is to create more protected areas — essentially national parks in the ocean.Beyond nature preserves，some conservationists are looking to more hands-on methods.One research center in the Florida Keys is exploring a form of natural selection to keep corals remaining.The reef system in the Keys has been hit hard by climate change and pollution，which is especially tough，because corals there help support fisheries worth ＄100 million every year.
    To keep the wild ecosystem alive，Erinn Muller，the center's director，and her team are harvesting samples of the corals that survived the environmental stress naturally，keeping them to make them reproduce，and then reattaching them to the reef.They have 46，000 corals on plastic frames under the sea.So far，the center has regrown over 70，000 corals from five different species on damaged reefs.
    In The Bahamas，Ross Cunning，a research biologist at Chicago's Shedd Aquarium，focuses on corals with genes that could make them natural candidates for restoration projects.He published a study of two Bahamian reefs，one that survived an extreme 2015 heat wave，and one that didn't. "We think their ability to deal with these higher temperatures is built into their genes，" says Cunning.There's evidence of corals evolving more quickly to resist rapidly warming climate.The big question scientists need investigate，adds Cunning，is how much more heat corals can adapt to.

（1）What does the underlined word "halt" in the first paragraph mean？ ____
A.End.
B.Develop.
C.Strengthen.
D.Weaken.
（2）What do Muller and her team do to save corals？ ____
A.Restore the damaged reefs.
B.Grow corals by hand underwater.
C.reate more protected areas.
D.Move corals to unpolluted areas.
（3）What do Cunning's words suggest？ ____
A.Many corals have been genetically improved.
B.Cooling down the waters is key to rescuing corals.
C.Reasons for corals surviving heat waves are shocking.
D.The highest temperature corals can survive is unclear.
（4）Which can be a suitable title for the text？ ____
A.Relationship between corals and algae
B.Efforts made to save corals
C.Impact of climate warming on corals
D.Survival crisis faced by coral reefs