Question

dogs have a reduced nonfunctional digit on their paws known as a dewclaw. what is this an example of?
○ analogous structure
○ homologous structure
○ vestigial structure
○ mutated structure

Explanation:

A vestigial structure is a remnant of a structure that had a function in an early ancestor. The dewclaw in dogs is non - functional (does not play a major role in locomotion like the other digits) and is a reduced structure, which fits the definition of a vestigial structure.
An analogous structure has a similar function but different evolutionary origins. A homologous structure has a similar evolutionary origin but may have different functions. A mutated structure is a structure that has changed due to a mutation, but the key here is the non - functional and reduced nature (vestigial aspect) rather than just being mutated.

Answer:

vestigial structure