The field that studies the Earth's physical structure and substance is known as geology. Geologists examine the composition, processes, and history of the Earth, including its rocks, minerals, landforms, and internal layers. This field encompasses various sub-disciplines, such as paleontology, geophysics, and mineralogy, and utilizes methods like field studies, laboratory analysis, and remote sensing. Geology is crucial for resource management, understanding natural hazards, and studying Earth's past climate and biological evolution.