When you look at text books they say one thing. When you get to the real studies, you see the problems with all of the theories that are treated as fact. Not only are almost all mutations harmful and almost all beneficial mutations only slightly beneficial (most, if not all, are actually lost information that makes them survive better in a particular environment, but less fit overall when considering all environments), so they cannot be selected for, but also DNA is so complex that many sections do one thing when read in one direction, another when read backwards, and yet another when you start reading in the middle. A mutation that might be beneficial in one of those spots is pretty much guaranteed to break it when read in another way for another function. Also the mutation rate is putting so many harmful mutations into the genome that, if we had actually been around for millions of years like we're told, we should have so many mutations that nobody should be able to live. Evolution only makes sense when you look at it from a birds eye view and don't look at the details. That doesn't even take into account how nobody has ever even gotten close to figuring out how the first cell came into existence. One of the best proven scientific laws is abiogenesis, life only comes from life and not non-life.

Textbooks are for indoctrination. They have lots of out-of-date science that has been disproven.