Question

what is the most likely reason that horses and mountain goats have hooves?
they have homologous structures because they have a common ancestor.
they have analogous structures because they have a common ancestor.
these are vestigial structures in both animals because they are not used.
these are similar structures due genetic mutations

Explanation:

• Homologous structures are anatomical features in different organisms that are similar in structure due to a common ancestor, even if their functions differ. Horses and mountain goats having hooves is an example of homologous structures as they share a common ancestor.
• Analogous structures are similar in function but not in structure and do not come from a common ancestor. Since the question is about a common ancestor, this option is incorrect.
• Vestigial structures are remnants of organs or structures that had a function in an early ancestor but are now reduced or non - functional. Hooves are functional in both horses and mountain goats, so this option is wrong.
• Similar structures due to genetic mutations is too vague and does not account for the evolutionary relationship (common ancestor) as well as the homologous structure concept.

Answer:

They have homologous structures because they have a common ancestor.