Hi
Before answering the question, we need to understand what homologous organs are?
These are basically different organs that are found in different animals which apparently look different however they have similar anatomical structure. These are called homologous organs and they are an excellent source that shed the light on evolution of different organisms.
Homologous organs of three animals:
1: Dolphin's flipper
2: A bird's wing
3: Human arm
Although these are three different organs of three different organisms but still they are homologous organs, this is because the anatomical features of these structures suggest that these have similar sort of arrangement of bones, and wing sub parts. This suggests that in past, all these three organisms have a common ancestor and later due to evolution, they evolved into new creatures.
Hope it helps!