Sentence:  These widely advertised products , which are used primarily for washing clothes , <WSD>are</WSD> based on high-sudsing , synthetic organic actives ( sodium alkylbenzenesulfonates ) and contain up to 50 % by weight of sodium tripolyphosphate or a mixture of sodium tripolyphosphate and tetrasodium pyrophosphate . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)