Final answer:
The human coccyx or tailbone is an example of a vestigial structure, which is a part of the body that remains from our ancestors and serves little to no current function. Vestigial structures are evidence of evolution and suggest a change from common ancestors.
Step-by-step explanation:
The human coccyx, or tailbone, is considered a vestigial structure. This means it's a part of our anatomy that has remained from our ancestors despite having little to no function today.
Initially, in our distant ancestors, the tailbone was part of a tail used for balance or other functions. Over time, as humans evolved and the need for a tail disappeared, this structure became vestigial.
The coccyx now serves as an attachment site for ligaments, muscles, and serves minor support when sitting, but it does not participate in balance or provide locomotion as tails do for other species.