Which of the following pairs is not an example of homology?

Wings of butterfly and wings of bird

The correct answer is Option (2)- Wings of butterfly and wings of bird

Whales, bats, Cheetah and human (all mammals) share similarities in the pattern of bones of forelimbs. Though these forelimbs perform different functions in these animals, they have similar anatomical structure – all of them have humerus, radius, ulna, carpals, metacarpals and phalanges in their forelimbs. Hence, in these animals, the same structure developed along different directions due to adaptations to different needs.

This is divergent evolution and these structures are homologous. The thorn and tendrils of Bougainvillea and Cucurbita represent homology.

Wings of butterfly and of birds look alike. They are not anatomically similar structures though they perform similar functions. Hence, analogous structures are a result of convergent evolution - different structures evolving for the same function and hence having similarity.