Dogs have a reduced nonfunctional digit on their paws known as a dewclaw. what is this an example of?

Mutation
Adaptations are the result of evolution in different living organisms. This process occurs amazingly through gene mutation but it takes a very long period in time. Adaptation processes occur to help species survive and thrive in the ecological balance of life. Structural adaptations are physical features of an organism that adapted through time. An example of this are the bills of a bird and the fur of bears that they generally need for their survival; birds for hunting, and bears to protect them from low climate areas.

The answer to this would be choice b (diplod)