On the contrary, The first reason why many people support the animal-testing’s existence is animals are suitable in experiment. It is because animals and human beings are very similar to each other in many ways, especially in biology. They have the same set of organs; heart, lungs, etc. that function similarly and tend to have the same reaction with humans. For instance, chimpanzees’ DNA is 99% similar to humans, and the genetics of mice are 98% similar to humans.13 Accordingly, animals have many chances to get the same illness with humans such as heart disease, cancer, and diabetes. In addition, thanks to the shorter life cycles than human beings, animals are better in making research subjects. For example, mice and rats are appropriate to long-term cancer research, partly because the lifespan of laboratory mice on average is only two or three years, so the researchers can study the effects of treatments, or medicines for a whole lifespan, or even for generations, which obviously would be impossible using human subjects in the experiments. With these evidences and examples, it is enough to say that using animals in experiments is irreplaceable, and animals are really fit for the experiments.