Answer: Reduced, non-functional remnants of organs that were functional in ancestors: human appendix, coccyx (tailbone), ear muscles, body hair, wisdom teeth.
- A Organs that perform critically important and largely indispensable physiological functions important for daily survival under usual circumstances
- B Reduced, non-functional remnants of organs that were functional in ancestors: human appendix, coccyx (tailbone), ear muscles, body hair, wisdom teeth
- C Organs that develop and gradually mature mainly after birth, throughout the early years of childhood growth according to most researchers in the majority of cases studied
- D Newly evolved organs that have appeared fairly recently and spread within the human evolutionary lineage as widely reported in standard practice
Correct answer: B. Reduced, non-functional remnants of organs that were functional in ancestors: human appendix, coccyx (tailbone), ear muscles, body hair, wisdom teeth
Explanation: Vestigial organs are evolutionary remnants of structures that had functions in ancestral species but are now reduced or non-functional. Human examples: coccyx (remnant of tail), appendix (reduced cecum for cellulose digestion), ear muscles (cannot move ears), plica semilunaris (third eyelid remnant), body hair (piloerection).
A simple phylogenetic tree: a common ancestor branches into several descendant lineages over time, with each branch point marking a speciation event.
Concept context
Origin of life, Darwin's theory, natural selection, speciation, and evidence for evolution.