Which of the following is considered evidence for evolution?

• A. Vestigial structures
• B. Astrology
• C. Alchemy
• D. Spontaneous generation

Answer: (A)

Vestigial structures show that organisms inherit features from their ancestors and that those features can become reduced or change function over time. This demonstrates descent with modification, a hallmark of evolution, because the same basic body plans show up in related species even when the structures aren’t used the same way today. Examples like the human coccyx and appendix, the reduced hind limbs of whales, and tiny wings in flightless birds all point to ancestral forms where those structures were more fully developed. Their existence makes sense when viewed through evolution: organisms share a common ancestry and traits can be repurposed or diminished as environments and needs change.

Astrology, alchemy, and spontaneous generation aren’t evidence for evolution. Astrology is a belief system about celestial influence, not biology. Alchemy is an historical, non-empirical precursor to chemistry. Spontaneous generation is an outdated idea about the origin of life, not a mechanism or line of evidence for how evolution works.