Earth´s Rock and Soil

                                                                            Vocabulary#12
rock: a naturally formed solid in the crust,made up of one or more minerals.

igneous rock: a rock formed when melted rock materials cools and hardens.

sedimentary rock: a rock made of bits of matter joined together.

fossil: any remains or imprint of living things of the past.

metamorphic rock: a rock formed under heat and pressure from another kind of rock.

humus: decayed plant or animal material in soil.

pollution: adding any harmful substances to Earth´s land,water,or air.

Rock cycle: rocks changing from one form into another in a never-ending series of processes.