Final answer:
Scientists learn about past organisms, species evolution, ecosystems, Earth's geological history, and mass extinctions by studying fossils in rock layers.
Step-by-step explanation:
By studying fossils inside rock layers, scientists can learn about the organisms that lived in the past and how these organisms have changed over time. Fossils provide valuable information about the evolution of various species and the development of different ecosystems. They can also help scientists understand the Earth's geological history, including the formation of continents, climate changes, and major events such as mass extinctions.
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