Question

There are several compelling pieces of scientific evidence that support the occurrence of evolution. Answer the following question using the choices provided. Each of the following terms may be used once, more than once, or not at all.
The presence of a humerus, radius and ulna bone in the limbs of all vertebrates indicates common ancestry. These limbs are called

• A. Fossil structures
• B. Vestigial structures
• C. Analogous structures
• D. Homologous structures
• E. DNA sequences

Answer 1

Answer: (D)

Homologous structures

A. Fossil structures are the fossil evidences that are obtained from the remains of plants and animals.

B. Vestigial structures are the structures that once performed an important function in the organism's body but with the course of evolution, they became non functional.

C. Analogous structures are the structures that have different basic structures but perform same functions.

D. Homologous structures are the structures that have same basic structure but perform different functions.

E. DNA sequences are formed by the arrangement of four nucleotides, adenine, thymine, guanine and cytosine.

Hence the presence of a humerus, radius and ulna bone in the limbs of all vertebrates that indicates common ancestry shows that they have a same basic structure but they are performing different functions in different organisms. Therefore, they are homologous structures.

So, the correct answer is 'Homologous structures'.