History and Debate of （Animal Rights）
Animals are used for research （in a variety of settings在各种情况下）, including举例： tests to determine the safety of drugs（测试药品的安全与否）, cosmetics（化妆品） and other substances. Whether or not humans should use animals for testing purposes（主语从句）, however, is a controversial subject. There are both pros and cons同意和不同意 to using animals for testing, but the scientific community, the government and society in general have yet to（还没有） reach a consensus on（达成共识注意介词用on） this ethical issue.
注意主题句提取，在写作中灵活运用：One of the primary advantages of animal testing is that it allows researchers to develop new medications and treatments, advancing the field of medicine and enhancing the health of society. 举例：For instance, many drugs used to treat or prevent cancer, HIV, diabetes, infections and other medical maladies have resulted from tests performed on animals. Many proponents支持者 of animal testing support the practice for this reason, even if they do not support testing cosmetics or other non-essential非生活必须品 substances on animals.
注意学习主题句如何提取，在雅思写作中加以运用。Animal testing also（不漏痕迹的过渡） enables scientists and researchers to test the safety of medications and other substances with which humans have regular contact. Drugs, for instance, may pose significant risks to humans, so testing them on animals first gives researchers a chance to determine drugs’ safety before human trials are performed. While scientists are cognizant知道 of the differences between humans and animals, the similarities are considered significant enough to produce relevant, useful data that they can then apply to humans. Thus, animal testing reduces harm to减少危害 humans and saves lives, not only because the exposure to risky substances is minimized, but because resulting medications and treatments have such positive impacts on the overall quality of life experienced by humans.
Critiques of Animal Testing
反面观点：One of the major disadvantages to animal testing is that a significant number of animals are harmed or die as a result of experiments and testing. Unfortunately, many of the substances used on animal subjects never receive approval for human use or consumption. Those who oppose animal testing consider this a very important point, because humans receive no direct benefits as a result of the deaths of these animals. Opponents反对者 also argue that animals are dissimilar enough from与不同 humans to make the results of animal tests unreliable. A related criticism is that testing induces stress in the animals, meaning that the subjects do not react to experimental substances in the same way that they might in more natural circumstances, making the results of experiments less valid.
Using animals as research subjects is also expensive, because the animals require food, shelter, care and treatment in addition to（除。。。之外，和） the costs of experimental substances. Long-term or multi-phase tests can increase the costs of the practice as well. The actual price paid for the animals is also worth consideration值得考虑; 解决方法：there are companies that breed and sell animals specifically for testing purposes.