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 Environmental Protection Agency estimates that showers account for nearly 1.2 trillion gallons each year--about one-sixth of all the water used in U.S. residences for bathing. Before 1994, showerheads typically had a flow rate of 5 Â½ gallons per minute. Since then, the Department of Energy has limited showerheads to 2 Â½ gpm to conserve not only water, but fuel for the water heater. Models that display a WaterSense label use no more than 2 gpm.