Which of the following is not an example of analogous organs.

The correct answer is Option (4) → Forelimbs of horse and wings of birds

Option (1) Flippers of penguins and flippers of dolphins — Analogous. NCERT gives the flippers of penguins and dolphins as an example of analogy: a bird and a mammal with different structures doing the same job of swimming.

Option (2) Eye of octopus and eye of humans — Analogous. NCERT names the eye of the octopus and of mammals: the eyes are built differently, but both form images.

Option (3) Wings of birds and wings of butterfly — Analogous. Wings of birds and of butterfly look alike and both are used for flight, but they are not anatomically similar.

Option (4) Forelimbs of horse and wings of birds — Not analogous. The forelimb of a horse and the wing of a bird are both vertebrate forelimbs with the same basic plan of bones but different jobs. So they are homologous, not analogous.

NCERT Extract:
What Are the Evidences for Evolution? – “… 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. Other examples of analogy are the eye of the octopus and of mammals or the flippers of Penguins and Dolphins.”