an element that is required in minute concentrations for normal growth and development; the body contains a total of <5 g of the element. Trace elements include fluorine (see fluoride), manganese, *zinc, copper, *iodine, cobalt, *selenium, molybdenum, *chromium, and silicon. They may serve as *cofactors or as constituents of complex molecules (e.g. cobalt in vitamin B12).
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