A blood alcohol concentration (BAC) or blood alcohol level (BAL) reflects the amount of alcohol in the body. Food, type and quantity of beverage, weight, sex, and rate of elimination determine the BAC after the consumption of alcohol.
The process of oxygen transfer in the gills of a fish is a good example of the benefits of countercurrent exchange. As oxygen poor blood meets an opposed flow of oxygen rich water, the oxygen begins to diffuse out of the water and into the blood stream.
The Gulf Stream is readily visible as the warmest water in the image. Waters moving in the western boundary currents adjacent to the major gyres (North and South Pacific and Atlantic basins and the Indian basin) transport large quantities of heat poleward from the tropics.