Sentence:  The differentiation however is not very much greater , as shown by the <WSD>fact</WSD> that Athabascan shows 3.46 stems per meaning slot as against 2.75 for Yokuts , with a slightly greater number of languages represented in our sample : 24 as against 21 . 
Meaning of the word marked with <WSD> tags:  a concept whose truth can be proved