All organisms depend on their environments for energy and the materials needed to sustain life: clean air, potable water, nutritious food, and safe places to live. For most of human history, increases in longevity were due to improved access to these necessities. Advances in agriculture, sanitation, water treatment, and hygiene have had a far greater impact on human health than medical technology.Although the environment sustains human life, it can also cause disease Lack of basic necessities is a significant cause of human mortality