Here are a few notes about the biological role of iron.
Iron compounds are essential to all life.
For example, it is an iron atom in haemoglobin that is responsible for carrying oxygen around the blood stream. The following gives the abundances of the elements in humans . Just enter your weight in either kilograms or pounds. In some browsers, after entering your weight you may have to click outside the text entry box to make the calculation work. Elements for which there are no data will always give a value of zero for the weight, no matter what you put in the weight box.