Are dolphin fin and fish tail homologous structure?

Dolphin fins and fish tails are not homologous structures; they are examples of convergent evolution. While both serve similar functions in locomotion, dolphin fins are modified forelimbs (homologous to the arms of other mammals), whereas fish tails are derived from the body and are part of the fish's vertebral structure. Thus, their similarities arise from adapting to similar environments rather than from a common evolutionary origin.