Give an example of a vestigial structure.

• A. A wing used for flight
• B. Human appendix or whale pelvic bones.
• C. A fully functional tail
• D. A nonfunctional bump on bone

Answer: (B)

Vestigial structures are remnants from ancestors that were once functional but have become reduced or carry little to no function in the present organism. An example is the human appendix, which in our ancestors helped digest plant material but is now largely vestigial for digestion. Whale pelvic bones are another classic case, left over from hind limbs that whales’ ancestors used for walking. These remnants illustrate how species evolve over time while keeping traces of their evolutionary history. The other options describe features that are actively used (a wing for flight, a fully functional tail) or a nonfunctional bump that isn’t a historical remnant of a once-functional structure.