Consider the following examples:
1) Wings of a bat
2) Flippers of a whale
3) Wings of a butterfly
4) Limbs of a human
Which of the following are homologous organs?
1, 2 and 4
Homologous organs are those that have similar internal structure but perform different functions. Wings of a bat, flippers of Whale and limbs of Human beings are all homologous to each other as they have a common origin, hence similar internal structure (bones that comprise them). On the other hand, wings of a butterfly though perform similar function do not have the same common origin as the other organs listed and hence is not homologous to them. They are instead analogous organs.