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 warm air goes to the poles, cools down and sinks, and then circulates back. Scientists call this Hadley Circulation. The weather on Uranus works very differently. This is because Uranus is tilted over onto its side, rotating at an angle of 99-degrees.