You are being mislead by creationist websites. There are plenty of things that are impossible for evolution, starting with those noted by Charles Darwin in 1859:If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.
If it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection.
- both from Chapter Six of Origins.
The first of these was the trigger for Professor Behe’s work on Irreducible Complexity. A valiant, though failed, attempt to meet Darwin’s challenge.
There are many different ways to measure similarity, and the 70% figure applies to a small part of the two genomes. Measuring overall similarity over the entire genomes gives figures in the range 95% to 98%. Again your creationist sources are lying to you. There is no scientific support for YEC so YEC websites have to rely on lies. Why do you trust liars?
rossum