(2016河南郑州二模,D)题材:科普知识词数:355限时:5分钟
People have been wondering why elephants are not likely to 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 has found that elephants carry a large number of genes that stop tumors(肿瘤)developing. To be precise①, they found 20 copies of an anti-tumor gene called TP53 in elephants. Most other species, including humans, only carry one copy.
