Sentence:  What concerns him much more <WSD>is</WSD> the relationship of diet to the nation 's No. 1 killer : coronary artery disease , which accounts for more than half of all heart fatalities and kills 500000 Americans a year - twice the toll from all varieties of cancer , five times the deaths from automobile accidents . 
Meaning of the word marked with <WSD> tags:  be identical to; be someone or something