Personaly I don't think that there are many pros about this subject, but I've written down a few. Pros:
There are vaccines for most of the diseases. Like the ones you'll recive when you're an infant, wich are very important. If you have a deadly disease, like cancer for example, you can prolong your life for years, if you discover it early enough. Thanks to the science and research with animals. In some cases you can also help sick animals by doing tests on them.
In my opinion there are more cons. To some lenght I do agree with animalactivists when they say that ”we” kill the animals for no reason what so ever, but at the same time I don't think they realize that it's thanks to this that many of them are alive today. This is what I think. Cons:
They do many unneccessary tests over and over even though it already exists workable vaccines. Then they simply make the animals suffer. Why do certain when they know that animals react diffrently from humans? Some doctors only does the tests to rise in their position, to get better paid. They would go so far as giving the monkeys a cigarette, to get cancer, just so they can do tests on it! Some of the medicins isn't even legas or at least not recognized by WHO. So they have done som painful and cruel tests on the animals for their own gain. Cosmetics that are tested on animals doesn't have to be done. They're not the ones who will use it in the end anyway, test it on us humans instead!Or is the makeup ingredients so dangerous that you get permenantly damaged?