The element essential for human life that is present in water is oxygen. Water, chemically represented as H2O, is composed of two hydrogen atoms and one oxygen atom. Oxygen is critical for cellular respiration, allowing cells to convert nutrients into energy. Additionally, water plays vital roles in maintaining body temperature, facilitating metabolic processes, and transporting nutrients and waste within the body. The presence of sufficient hydration, which includes water and oxygen, is crucial for overall health and functioning.