Q. Which among the following is homologous to a human arm?
Answer: Lateral Fin of a whale
Notes: The lateral fin of the whale consists of the same bones as a human’s arm, the radius, ulna, and humerus. These structures are considered to be homologous because the underlying structure is similar and, therefore, humans and whales share a common ancestor. The lobster’s leg, the reptile’s front leg, and the insect’s wing are analogous to the human’s arm. They have a common function but no common structure, and they do not share a common ancestor.