How do homologous structures show evidence of evolution?

Homologous structures are anatomical features in different species that share a common ancestry, despite serving different functions. For example, the forelimbs of humans, whales, and bats have similar bone structures but are adapted for various purposes like grasping, swimming, and flying. This similarity indicates that these species diverged from a common ancestor, providing evidence for the process of evolution. The presence of homologous structures supports the idea of shared genetic heritage and evolutionary adaptation over time.