Darwin was able to explain evolution with evidence, something Lamarck did not do.
Explanation:
Lamarck and Darwin both were scientists who tried to understand the concepts of evolution. Lamarck's theory of evolution was based upon how living organisms vary during their lifetime, and after that they pass these changes to their offspring. While on the other hand Darwin's theory was very much based upon evidences and practical explanation that is why his theory became accepted and Lamarck's wasn't.