中考英语易错题考前必刷练习卷分类汇编：阅读理解2020-2021学年牛津译林版

中考英语易错题考前必刷练习卷分类汇编：阅读理解 中考英语易错题考前必刷练习卷1（含答案）-2020-2021学年牛津译林版 ELEPHANTS have impressed us for centuries. They are big, clever, and kind. But what if someone told you that they may also hold the key to fighting cancer (癌症)?( People have been wondering why elephants do not develop cancer, even though they have lifespans (寿命) that are similar to humans, living for around 50 to 70 years. Now scientists believe they know why. A team at the University of Chicago, US has found that elephants carry a large number of genes that stop tumors (肿瘤) from developing. To be precise(exact), they found 20 copies of an anti-tumor gene called TP53 in elephants. Most other species, including humans, only carry one copy. According to the research, which was recently published on the online science network BioRxiv, the extra copies of the gene improved the animal’s sensitivity to DNA damage. This lets the cells quickly kill themselves when damaged before they can go on to form deadly tumors.