A type of social interaction in which one person voluntarily does something for another, expecting a reward in turn. a
groupthink
b
social exchange
c
cooperation
d
conformity

Ruth is 44 years old. at her medical checkup, her doctor notices that ruth's lymph nodes are enlarged. after some blood tests and a ct scan, ruth's doctor diagnoses her with ( ) , a cancer that typically starts in the lymphocytes and can spread to the bone marrow.