雅思作文是一门相对较难的科目，更注重同学们对话题的敏感度，才能有句子可写。下面是沪江小编为大家介绍的雅思写作范文整理，大家可以进行参考。
观点调录: Pro 1 Animals often make better research subjects than human beings because of their shorter life cycles. Laboratory mice, for example, live for only two to three years, so researchers can study the effects of treatments or genetic manipulation over a whole lifespan, or across several generations, which would be infeasible using human subjects.[29] [9] Mice and rats are particularly well-suited to long-term cancer research, partly because of their short lifespans. [30]
Cons 5 Drugs that pass animal tests are not necessarily safe. The 1950s sleeping pill thalidomide, which caused 10,000 babies to be born with severe deformities, was tested on animals prior to its commercial release. [5] Later tests on pregnant mice, rats, guinea pigs, cats, and hamsters did not result in birth defects unless the drug was administered atextremely high doses. [109] [110] Animal tests on the arthritis drug Vioxx showed that it had a protective effect on the hearts of mice, yet the drug went on to cause more than 27,000 heart attacks and sudden cardiac deaths before being pulled from the market.
Cons 3 Animals are very different from human beings and therefore make poor test subjects. The anatomic, metabolic, and cellular differences between animals and people make animals poor models for human beings. [52] Paul Furlong, Professor of Clinical Neuroimaging at Aston University (UK), states that "it's very hard to create an animal model that even equates closely to what we're trying to achieve in the human." [53] Thomas Hartung, Professor of evidence- based toxicology at Johns Hopkins University,argues for alternatives to animal testing because "we are not 70 kg rats."
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