Vestigial structures are...

Vestigial structures are...

• A. Reduced or unused remnants that once had function.
• B. Structures with identical function in related species.
• C. Structures that always remain fully functional.
• D. Structures that arise only by mutation.

Answer: (A)

Vestigial structures are reduced or unused remnants of features that were functional in ancestors. Over time, as lifestyles or environments change, these traits lose their original function or become much less important, yet persist in the organism as hints of evolutionary history. A classic example is the human appendix or coccyx, which show that our ancestors had a larger or different version of these structures. In whales, small pelvic bones indicate hind limbs of land-dwelling ancestors. This idea matches the statement describing a reduced or unused remnant that once had function. Other options describe structures that are still fully functional, or that have identical functions in related species, or that arise only by mutation, which don’t capture what vestigial means.

Vestigial structures are reduced or unused remnants of features that were functional in ancestors. Over time, as lifestyles or environments change, these traits lose their original function or become much less important, yet persist in the organism as hints of evolutionary history. A classic example is the human appendix or coccyx, which show that our ancestors had a larger or different version of these structures. In whales, small pelvic bones indicate hind limbs of land-dwelling ancestors. This idea matches the statement describing a reduced or unused remnant that once had function. Other options describe structures that are still fully functional, or that have identical functions in related species, or that arise only by mutation, which don’t capture what vestigial means.