What type of data do fossils primarily provide in studies of evolution?

• A. A record of change over time.
• B. A snapshot of present-day population genetics.
• C. The exact mechanism of natural selection.
• D. A forecast of future changes.

Answer: (A)

Fossils primarily provide a record of change over time. By comparing organisms from different rock layers, we can see how forms have evolved, when lineages appeared or disappeared, and how traits shifted across eras. Dating these fossils places them on a timeline, letting us reconstruct the sequence of evolutionary events and patterns of descent with modification. While this historical record can suggest how natural selection shaped traits, fossils don’t reveal the exact genetic mechanisms behind those changes. They also don’t offer a snapshot of present-day population genetics or a forecast of future changes, since they document past life rather than current gene frequencies or future trends.