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.
In the Indian Ocean, the countercurrent is present only during the winter. Equatorial countercurrents, driven by tropical surface wind patterns, flow in the opposite direction of the surface winds. There are large month-to-month changes in the strengths of the Pacific and Atlantic equatorial coun-tercurrents.