Sentence:  The tremendous emphasis on the 5 in the Lo Shu square - for purely mathematical reasons - and the fact that this number so neatly symbolized the heart and center of the universe , could well <WSD>explain</WSD> why the Old Chinese seem to have so revered the number 5 , and why they put so much stress on the concept of Centrality . 
Meaning of the word marked with <WSD> tags:  make plain and comprehensible