In science why is it important to have more than one piece of evidence to support your claim?

It is important to have more than one piece of evidence to make sure that the evidence is actually evidence. Or in other words, that the evidence is proven true. With only one piece of evidence, you can't be fully sure if calculations were correct, if the source was trustworthy, etc.

Multiple evidence is kinda like double checking math problems. If you don't do it, you can't be 100% certain the answer is correct.