Sentence:  The cells were washed three times with saline , anti human serum was added , the cells were resuspended , and the mixture was centrifuged at 1000 rpm for 1 min and examined for <WSD>agglutination</WSD> . 
Meaning of the word marked with <WSD> tags:  the building of words from component morphemes that retain their form and meaning in the process of combining