fens
... that fens are fed by mineral-rich groundwater, while bogs are fed by mineral-poor precipitation?
... that <b id="mwAtk"><a href="./Fen" id="mwAto" rel="mw:WikiLink" title="Fen">fens</a></b> are fed by mineral-rich <a href="./Groundwater" id="mwAts" rel="mw:WikiLink" title="Groundwater">groundwater</a>, while <a href="./Bog" id="mwAtw" rel="mw:WikiLink" title="Bog">bogs</a> are fed by mineral-poor precipitation?