Why does the author include this sentence in the paragraph 2

Vvnici prece di evidence would best support teason #to the history of using animals for research extends asfar back as 322 bce, when early greek physician-scientists, such as aristotle and erasistratus,performed various experiments on living animals.0 animal research played an essential role in thedevelopment of herceptin and tamoxifen, twomedications that have already saved the lives ofthousands of women who have been diagnosed withbreast cancer.even those who believe in testing on animals when it isnecessary for vital medical research practice what isknown as "the 3 rs"-reduction, refinement, andreplacement to reduce the number of animals usedfor testingbiologists believe that chimpanzees share at least 98.4percent of the same dna as humans and gorillas shareat least 97 percent, making primates a popular andlikely choice for the testing of products intended for humans