The United States Geological Survey estimates that (as of 2005, the most recent year for which data is available) we withdraw 410 billion gallons of water a day, including both fresh and saline water. Most (80%) of these withdrawals go to thermoelectric power plants (for cooling) and agriculture (for watering crops).
Level 4 is the hair color level that is represented as dark brown. It is one of the most common natural hair colors and also very commonly found in hair dye. Level 4 is also common in red or...
Hair color is determined by two different forms of pigment: eumelanin (which is the largest influence) and phenomelanin. Eumelanin is a black pigment, and phenomelanin is a red or yellow pigment. Hair color is determined by three factors having to do with pigments: how much pigment is present, to what degree a eumelanin or phenomelanin is present and how close together the melanin (pigment) granules are. The more eumelanin a person has, the darker his hair will be.