Sentence:  The cells were washed three times with saline , anti <WSD>human</WSD> serum was added , the cells were resuspended , and the mixture was centrifuged at 1000 rpm for 1 min and examined for agglutination . 
Meaning of the word marked with <WSD> tags:  any living or extinct member of the family Hominidae characterized by superior intelligence, articulate speech, and erect carriage