Elements combine in a variety of Earth materials. – Organic compounds – Carbon-containing compounds. • Most are residue from once-living creatures. • Include wood, peat, lignite, coal, and oil. • Geologically rare (decomposes in contact with oxygen).
Elements combine in a variety of Earth materials.–Organic compounds – Carbon-containing compounds.•Most are residue from once-living creatures.•Include wood, peat, lignite, coal, and oil.•Geologically rare (decomposes in contact with oxygen).