Question

how do organisms form carbon films?
organisms turn into rock.
residue is left on rocks when organisms decay.
hollow forms are left in sediment by decaying organisms.
organisms leave evidence of their activities, such as footprints.

Explanation:

Carbon films form when soft parts of organisms decay, leaving behind a thin layer of carbon residue on rock surfaces. The other options describe different fossil types: option A refers to petrification, option C describes molds, and option D is trace fossils.

Answer:

B. Residue is left on rocks when organisms decay.