Please elaborate.
You see, there's nothing to 'believe in' with science
Don't kid yourself friend. Read "The structure of scientific revolutions" by Kuhn.
I've mentioned this on several of these threads. There is an identical error in the DNA of people, chimps, gorillas, et al., that prevents the formation of ascorbic acid (vitamin C). This mutation is not found in any other mammal. (the only other vitamin-c-dependent animal is the guinea pig, and it has a different mutation blocking the synthesis of ascorbic acid)
The question arises, why? The obvious answer (to me at least) is that all the species inherited it from a common ancestor. Some anti-Evolutionists have countered that it shows the Designer used the same parts in different designs (ignoring what this says about D's quality control), or that it shows that this particular gene in great apes and people is somehow more vulnerable to mutation (ignoring what this says about the human and ape genes being more alike before the mutation, and also ignoring the odds of the *exact same* mutation occuring six times).
More precisely, people, chimps, and the other great apes have been thought to be related since at least Darwin's time on anatomical grounds. Finding the *exact same* mutation in these species is independent evidence of such a relationship.
Do a web search, this is by no means the only case like this