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The red colour of the blood is the colour of the hemoglobin. 1_______. As iron carries oxygen, people who do not have enough iron do not get enough oxygen for their normal activities. 2_______. A small quantity of iodine is also necessary for good nutrition – probably less than one ten-thousandth of a gramme daily. Deficiency of iodine results in an overgrowth of the thyroid gland. 3_______. Fluorine is a constituent of the enamel of the teeth but it is absent from most foods. So many cities now add traces of fluorine to the water supply. 4_______.
The hemoglobin contains one atom of iron among its ten thousand atoms
Iron is found in kidney, liver, other meat products, some vegetables, dried fruits and bread
Sea foods are rich in this element
Besides small amounts of fluorine are added to various toothpastes