Rukwa Valley
... that the Rukwa Valley in southwestern Tanzania is sparsely populated because of its difficult environment?
... that the <b id="mwDp0"><a href="./Rukwa_Valley" id="mwDp4" rel="mw:WikiLink" title="Rukwa Valley">Rukwa Valley</a></b> in southwestern <a href="./Tanzania" id="mwDp8" rel="mw:WikiLink" title="Tanzania">Tanzania</a> is sparsely populated because of its difficult environment?