The earth's energy budget involves tracing the amount of energy that flows into and out of the earth’s climate system, the destination of the energy and knowing if there is a balance between the incoming and the outgoing heat energy. The information produced by the earth's energy budget helps in establishing the earth's climate and in predicting future effects of global warming.
Arteries carry oxygenated blood away from the heart. Veins carry the blood back to the heart. Veins contain valves that ensure blood flows in only one direction. Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.
