How do fossils provide evidence about Earth’s past?

• A. They indicate future climates.
• B. They measure current atmospheric composition.
• C. They show which organisms lived long ago and the environments they inhabited, helping scientists infer past climates and ecosystems.
• D. They determine plate boundaries.

Answer: (C)

Fossils provide a record of ancient life and the environments they inhabited. By looking at which species are preserved in specific rock layers and the kinds of sediment surrounding them, scientists infer the conditions those organisms lived in and how those conditions changed over time. For example, finding tropical plants or marine organisms in rocks well inland suggests warmer, wetter climates in the past, while shifts in fossil communities indicate ecological transitions. The context of the rock—its age, type, and chemistry—helps reconstruct ancient climates and ecosystems. Fossils don’t predict the future or measure the present atmosphere, and they don’t directly pinpoint plate boundaries, but they do reveal how life and environments differed long ago.