The Earth and Atmosphere Crossword Puzzle

QUESTIONS LIST: atmosphere : the gas layer that surrounds the earth, oxygen : the useful gas that we breathe, nitrogen : the gas that is most common in the atmosphere, crust : the outer layer of the earths composition, sedimentary : soft rock that fossils can be found in, metamorphic : rock that is created under heat and pressure (marble), igneous : rock that is made when magma cools, fossil : the remains of a creature that lived millions of years ago, carbon dioxide : the gas that humans breathe out, acid rain : something that can cause damage to statues and rock, rock cycle : the process by which a rock can change from one type to another