Sentence:  It is assumed that the <WSD>iodine</WSD> released from the iodotyrosines remains in the iodide pool of the thyroid , where it is oxidised and re-incorporated into thyroglobulin . 
Meaning of the word marked with <WSD> tags:  a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks)