Evolution is a SCIENTIFIC THEORY. A scientific theory theory that has stood for over 150 years without being falsified is as close to fact as science can come. It can never be positively proven.

Evolution has proven extraordinarly useful to science, becasue of its organizing power, and it predicatory power. For instance, Darwin predicted that the earliest human ancestors would be found in Africa. He was right. This is why evolution is considered as a fact.

you are obviously either not a real student of biology, or are a bad student, because this a basic tennet of all science.