Question

fossils
quiz complete
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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:

To determine how organisms form carbon films, we analyze each option:

• "Organisms turn into rock" describes petrification, not carbon film formation.
• "Residue is left on rocks when organisms decay" is correct. When organisms decay, the volatile components (like hydrogen, oxygen, nitrogen) escape, leaving behind a thin layer of carbon residue on the rock, which forms the carbon film.
• "Hollow forms are left in sediment by decaying organisms" describes mold formation, not carbon films.
• "Organisms leave evidence of their activities, such as footprints" describes trace fossils, not carbon films.

Answer:

B. Residue is left on rocks when organisms decay.