Sentence:  Calcium , <WSD>phosphorus</WSD> and iron are present in worthwhile amounts , and eleven other minerals also have been found in varying trace amounts . 
Meaning of the word marked with <WSD> tags:  a multivalent nonmetallic element of the nitrogen family that occurs commonly in inorganic phosphate rocks and as organic phosphates in all living cells; is highly reactive and occurs in several allotropic forms