How do scientists use DNA to support evolution?

DNA supports evolution because all life on Earth carries DNA, and evolution happens only after DNA changes. These changes are called mutations and happen spontanoulsy from flawed DNA copying or from mutagens, such as X-rays or chemicals.

DNA supports evolution because it carries genetic information. This genetic information is then passed on to offspring through DNA, which basically allows traits to be inherited, which allows natural selection to take place because the better genes survive, it carries the information and variation that ultimately fuels natural selection, driving evolution.