Vocabulary #14

1. rock: a naturally formed solid in the crust, made up of one or more minerals.
2. igneous rock: a rock formed when melted rock material cools and hardens.
3. sedimentary rock: a rock made of bits of matter joined together.
4. fossil: any remains or imprint of living things of the past.
5. metamorphic rock: a rock formed under heat and pressure from another kind pf rock.
6. humus: decayed plant or animal material in soil.
7. pollution: adding any harmful subtances to Earth's land, water, or air.
8. rock cycle: rocks changing from one form into another in a never-ending series of processes.