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 are formed when an organism decays. During this process, the organic material (except for carbon) in the organism is removed. The carbon - rich residue is left on the rock.

• Option 1: Organisms turning into rock is a general process of fossilization (like petrification) but not specific to carbon - film formation.
• Option 3: Hollow forms left in sediment by decaying organisms describe molds, not carbon films.
• Option 4: Organisms leaving evidence of their activities (such as footprints) are trace fossils, not carbon films.

Answer:

Residue is left on rocks when organisms decay.