Your kidneys are complex organs. They regulate the amount of water lost from the body and get rid of waste products, especially urea. Urea is made when any excess amino acids are broken down in your liver.
Middle Class Income for a Family. The annual average income for a middle class family of four is approximately $70, 354. This is based on a 2006 report by the U.S. Census for a family of four. This figure is in the middle of the range of incomes for this section of the population. The median income during this time for all households was $48,561.
DEFINITIONS OF A MIDDLE CLASS INCOME. Standard Definition: $25,000-$100,000 a year is what most would consider as a middle class income. The $75,000 spread accounts for the wide cost of living differential between places like New York City and Fargo, North Dakota. Everybody who lives in NYC or San Francisco will tell you that $25,000 a year is poor.