Final answer:
Organisms form carbon films when they are preserved in sedimentary rocks. Decay of soft tissues leaves behind a thin film of carbon, and over time, sediment hardens into rock.
Step-by-step explanation:
Organisms can form carbon films when they get preserved in sedimentary rocks. This process occurs when the soft tissues of an organism decay, leaving behind a thin film of carbon. Over time, the sediment surrounding the organism hardens into rock, preserving the carbon film.
For example, a leaf falling into a body of water may get buried in sediment. As the sediment layers accumulate, pressure and time transform the sediment into rock. The decomposed leaf leaves behind a carbon film in the rock, providing a record of the leaf's structure.
Learn more about Formation of carbon films in organisms