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.
Equatorial counter currents. A large amount of water is driven westward due to the north and south equatorial currents. Due to the coriolis effect, it piles up on the western margins, making it up to 2 meters higher up than the water on the eastern side. Then, under the force of gravity, it flows eastward and counter to the adjoining continental currents.