Environmental science is a multi-disciplinary field that studies the interaction between the natural world and human activities. It includes disciplines like chemistry, physics, biology and more. Environmental science examines sources, reactions, transport, effects and fate of physical and biological substances in air, water and soil, and how human actions impact these. The environment consists of the atmosphere, hydrosphere, lithosphere and biosphere. It is made up of physical elements like land, water and climate, biological elements like plants and animals, and cultural elements like economic and social factors.