The oxygen cycle describes the various forms in which oxygen is found and how it moves through different reservoirs on Earth. There are three major reservoirs of oxygen: the atmosphere, biosphere, and lithosphere. Some people also consider the hydrosphere, a subdivision of the biosphere, to be the fourth reservoir
Six <span>characteristics are used to describe living things. </span>To be considered alive, an object must exhibit all of the characteristics<span> of </span>living things<span>.</span> B. 6
