All of these provide evidence of evolution - anatomy through vestigial organs, embryology through that whole 'ontogeny recapitulating phylogeny' thing, and molecular biology through diverging genetic sequence relationships. But the fossil record contains anatomical evidence and even fossilized embryos which can be analyzed much like modern anatomy or embryology can. But molecular biology is unstable and breaks down over time, so it's impossible for it to be preserved in fossils.
