Questions: Which of the following pairs are the best examples of homologous structures? owl wing and hornet wing bat wing and bird wing bones in the bat wing and bones in the human forelimb eyelessness in the Australian mole and eyelessness in the North American mole

The answer is the third one: bones in the bat wing and bones in the human forelimb.

Explanation for each option:

1. Owl wing and hornet wing: These are not homologous structures. While both are used for flying, they do not share a common evolutionary origin. Owl wings are vertebrate structures with bones, feathers, and muscles, whereas hornet wings are invertebrate structures made of chitin.

2. Bat wing and bird wing: These are examples of analogous structures, not homologous structures. Both are used for flying, but they evolved independently in bats and birds. The underlying bone structures are different, reflecting their separate evolutionary paths.

3. Bones in the bat wing and bones in the human forelimb: These are homologous structures. Both share a common evolutionary origin and have similar bone structures (humerus, radius, ulna, etc.), even though they have adapted to different functions (flying in bats and manipulation in humans).

4. Eyelessness in the Australian mole and eyelessness in the North American mole: This is an example of convergent evolution, where similar traits evolve independently in different species due to similar environmental pressures. The eyelessness in these moles is not due to a common ancestor but rather to similar adaptations to their subterranean lifestyles.

Summary: The best examples of homologous structures are the bones in the bat wing and bones in the human forelimb, as they share a common evolutionary origin and similar structural features.