How many of the following are examples of homology?A. Vertebrate hear…

The correct answer is Option (2) → Three

Homologous structures have the same basic structure but perform different functions; they come from common ancestry through divergent evolution. Analogous structures do the same function but are not anatomically similar; they come from convergent evolution.

A. Vertebrate hearts — Homology. NCERT gives vertebrate hearts and brains as further examples of homology.

B. Thorn of Bougainvillea and tendril of Cucurbita — Homology. Both are modified stems, one for protection and the other for climbing.

C. Flippers of penguins and of dolphins — Analogy. A bird and a mammal have come to have similar flippers for swimming in a similar habitat.

D. Forelimbs of whales, bats, cheetah and human — Homology. All four have humerus, radius, ulna, carpals, metacarpals and phalanges, though they swim, fly, run or hold things.

E. Wings of butterfly and of birds — Analogy. Both are used for flying, but they are not anatomically similar.

So A, B and D are examples of homology, which makes three.

NCERT Extract:
What are the Evidences for Evolution? – “… For example whales, bats, Cheetah and human (all mammals) share similarities in the pattern of bones of forelimbs (Figure 6.3b). … This is divergent evolution and these structures are homologous. Homology indicates common ancestry. Other examples are vertebrate hearts or brains. In plants also, the thorn and tendrils of Bougainvillea and Cucurbita represent homology (Figure 6.3a).”
What are the Evidences for Evolution? – “… Homology is based on divergent evolution whereas analogy refers to a situation exactly opposite. Wings of butterfly and of birds look alike. They are not anatomically similar structures though they perform similar functions. … Other examples of analogy are the eye of the octopus and of mammals or the flippers of Penguins and Dolphins.”

Figure 6.3 Example of homologous organs in (a) Plants and (b) Animals