Sentence:  In general , friendly contact with a member followed by contact with a clergyman will account for a major share of recruitment by the churches , making it quite evident that the extension of economic integration through co-optation is the principal <WSD>form</WSD> of mission in the contemporary church ; economic integration and co-optation are the two methods by which Protestants associate with and recruit from the neighborhood . 
Meaning of the word marked with <WSD> tags:  a category of things distinguished by some common characteristic or quality