AP BIOLOGY

Detailed explanation-1: -Kidneys: These organs work constantly. They filter your blood and make urine, which your body eliminates. You have two kidneys, one on either side of the back of your abdomen, just below your rib cage. Each kidney is about as big as your fist.

Detailed explanation-2: -The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule.

Detailed explanation-3: -The kidney excretes toxins through essentially 3 mechanisms: (1) filtration through the glomeruli; (2) passive diffusion, typically from the distal tubules; and (3) active processes where the toxins are transported from the blood as well as into the urine.

Detailed explanation-4: -Urea is made when foods containing protein (such as meat, poultry, and certain vegetables) are broken down in the body. Urea is carried in the blood to the kidneys. This is where it is removed, along with water and other wastes in the form of urine.