Geology is the study of the Earth, including its composition and structure, the processes that act on it and the history of life it contains. Some of the key topics in geology are the layers within the Earth, different rock types, geological timescales, volcanoes, earthquakes, fossils, mountains, rivers, lakes, oceans, deserts and glaciers. Geology examines the formation and distribution of rocks, minerals, fossils and natural resources along with the natural hazards that can impact human civilization.