fact is we don't need to. Animal testing is used as a way to fasttrack medicines and cosmetics as they can use a different animal depending on the experiment for a favourable response. According to tests on rats citric acid is deadly yet arsenic is ok, chocolate would never have passed testing on dogs. animal tests are ideal for pharma/cosmetics companies as if they fail the tests they can ignore the results by claiming species incompatability yet if they want a more favourable result they simply test on a species that doesn't get the side effect. Also as they can then claim it has been tested these products can then pass onto the market with no further obstructions. The reason it still is allowed at all is a combination of vested interests by political powers and misinformation from within the industry itself.
As for the dissection for schoo; requirement try the info at
http://www.dissectionalternatives.org/ Legally they can't force you to do any class that may be against your ethical code or beliefs. You are entitled to refuse though you may get detention for doing so ut personally considered it worth it. Anyway good luck.