A single night of taking the drug Ecstasy   can cause serious brain damage and speed up the start of Parkinson's disease , scientists say. Just two or three Ecstasy tablets can permanently destroy brain cells that affect movement and reasoning, according to American research that links the drug to Parkinson's for the first time. A study by a team at Johns Hopkins University in Baltimore, Maryland, involving squirrel monkeys and baboons   found that both species suffered permanent damage to key cells, which are lost in Parkinson's, after receiving three low doses of Ecstasy at three-hour periods. The study is particularly important because baboons are one of the best animal models for the human brain. George Ricaurte, who led the research, said that the widespread abuse of drug might have caused severe damage. "The most troubling result is that young adults using Ecstasy may be increasing their risk of developing Parkinsonism as they get older." Alan Leshner, a former director of the US National Institute on Drug Abuse, said, "This study emphasizes the multi-aspect damage that Ecstasy causes to users. We've long known that repeated use damages brain cells. But this study shows that even very occasional  use can have long-lasting effects on many different brain systems. It sends an important message to young people: don't experiment with your own brain." Janet Betts, a mother whose teenage daughter Leah died after a single Ecstasy tablet in 1995, said, "This comes as no surprise. But people can't see the effects at first, and they say it won't happen to them. We'll see the symptoms later, just as we have with smoking." Why are squirrel monkeys and baboons involved in the experiments?
Because these animals usually take drugs. Because their brain is similar to human beings. Because there is a model in the animals' brains. Because they will soon get well after the experiment.
Question: A single night of taking the drug Ecstasy   can cause serious brain damage and speed up the start of Parkinson's disease , scientists say. Just two or three Ecstasy tablets can permanently destroy brain cells that affect movement and reasoning, according to American research that links the drug to Parkinson's for the first time. A study by a team at Johns Hopkins University in Baltimore, Maryland, involving squirrel monkeys and baboons   found that both species suffered permanent damage to key cells, which are lost in Parkinson's, after receiving three low doses of Ecstasy at three-hour periods. The study is particularly important because baboons are one of the best animal models for the human brain. George Ricaurte, who led the research, said that the widespread abuse of drug might have caused severe damage. "The most troubling result is that young adults using Ecstasy may be increasing their risk of developing Parkinsonism as they get older." Alan Leshner, a former director of the US National Institute on Drug Abuse, said, "This study emphasizes the multi-aspect damage that Ecstasy causes to users. We've long known that repeated use damages brain cells. But this study shows that even very occasional  use can have long-lasting effects on many different brain systems. It sends an important message to young people: don't experiment with your own brain." Janet Betts, a mother whose teenage daughter Leah died after a single Ecstasy tablet in 1995, said, "This comes as no surprise. But people can't see the effects at first, and they say it won't happen to them. We'll see the symptoms later, just as we have with smoking." Why are squirrel monkeys and baboons involved in the experiments?
A. Because these animals usually take drugs.
B. Because their brain is similar to human beings.
C. Because there is a model in the animals' brains.
D. Because they will soon get well after the experiment.
Answer: