It' seasy for us to take the natural world for granted. We breathe oxygen, drink water, and eat food grown in soil with little thought to the origins of these critical elements. Where do they come from? The natural world provides them-for free.

Green plants give off oxygen as a byproduct of photosynthesis, the process by which they make food. Plant/bacteria partnerships convert nitrogen, an essential component of protein, to a useable form. The vegetation in ecosystems also regulates freshwater by
returning some moisture to the atmoshere and by filtering water through the ground to replenish rivers and streams.

Built from eroded rock, soils are made fertile by the decay of organic matter. Organisms in the soil break down and recycle dead plant and animal matter. Roots anchor soil in place and help to prevent erosion. Without all of these natural processes, life would be impossible for all of us.