Animal experimentation is the backbone（支柱） of American research and treatment of disease． Each year, 17 to 22 million animals are sacrificed in the name of science．While 90 percent of them are rats and mice, 180,000 dogs, 50,000 cats．61,000 monkeys and 554,000 rabbits are done away with in Laboratories operated by industry and government．
But the public has raised an outcry over these deaths．Spurred vivid reports of cruelty, the animal rights movement is made up of 7,000 organizations with 10 million members．They've documented cases in which monkeys were isolated in steel tanks for 45 days and dogs were bombarded with radiation or chemicals until they bled from the mouth．
Scientists say such incidents are rare．I aws have been passed to govern testing．Many research centers now have committees to review all proposed animal experiments, and computers can be used in place of animals in many experiments．But scientists say they can't do without animals to test new drugs and treatments on animals to make sure they're safe for humans．Animal experiments produced vaccines or treatments for diseases such as diabetes（糖尿病）, and techniques used in open heart surgery．They're important to efforts to find a treatment for AIDS．
Animals rights activists have shown they will go to almost any length．One New York researcher received more than 10,000 protest letters following publicity other experiments in which she gave drugs to monkeys．The researcher was studying drug addiction．A protester was arrested in Connecticut for placing a pipe bomb outside a company that used animals in tests．After fires and break-ins, many labs have bought electronic locks and alarms for protection．Other targets of the animal rights movement are the fur industry, farms, and school biology classes in which children dissect（解剖） frogs．
The movement has scored some successes．A dozen states no longer allow pounds- places that accept dogs and cats that have no homes to sell animals to scientists．Scientists claim the cost of their work will rise as a result．
The battle between scientists and activists raises a basic question: Can modern society be both humane in its treatment of living things and advanced in its treatment of disease? It seems certain there will be new restrictions placed on the use of animals in scientific experiments．
62．Which of the following is the main idea of the passage?
A．Mice and rats make the best subjects for experiments．
B．Scientific experiments can be carried out without animals．
C．Fewer animals should be taken to laboratories．
D．Americans are questioning the use of animals in experiments．
63．Animal experiments will probably continue because         .
A．there are enough regulations to protest animals from abuse
B．they are critical for understanding and curing human disease
C．the groups that oppose them aren't very big or powerful
D．scientists insist they are harmless
64．What do proponents （supporters） of animal rights do to convince people of their opinion?
A．They treat their own pets kindly．
B．They explode bombs at laboratories that conduct scientific tests．
C．They give examples of animals that were mistreated in labs．
D．They point out the diseases that have been cured by scientists．
65．The underlined word "outcry" （in Paragraph 2） probably means         .
A．protest       B．protect       C．scream             D．alarm