Four students A, B, C and D reported the following set of organs to be homologous. Who is correct?

Correct Option: D

Explanation:

Homologous organs are organs in different species that share a common basic structural design and developmental origin (inherited from a common ancestral template) but perform different functions to adapt to different environments.

• Option D is correct: The forelimbs of a cow (mammal), a duck (bird), and a lizard (reptile) are homologous organs. They all share the same basic skeletal framework of vertebrate forelimbs, which is inherited from a common ancestor, but they are modified to perform different functions (walking, swimming/paddling, and crawling respectively). This reflects the text's assertion in Section 8.1 that inheritance provides a 'common basic body design' with modifications.

Why other options are incorrect:

• Option A (Wings of a bat and a butterfly): These are analogous organs. They perform the same function (flying) but have completely different structural designs and origins (a bat's wing is a fold of skin stretched between elongated fingers, whereas a butterfly's wing is a membranous extension of the exoskeleton).
• Option B (Wings of a pigeon and a bat): While both are vertebrate forelimbs, their designs specifically as wings are analogous. A bird's wing is supported by the arm bones and covered with feathers, whereas a bat's wing is a patagium (skin membrane) stretched mainly between elongated digits. Thus, their flight structures evolved independently.
• Option C (Wings of a pigeon and a butterfly): These are analogous organs because they have different structural designs and origins but perform the same function of flight.