Bartrop and Colleagues Compared the Immune Systems of 26 People

Multiple Choice

Bartrop and colleagues compared the immune systems of 26 people whose spouses had died 8 weeks earlier with those of 26 matched control-group participants whose spouses had not died. The blood samples revealed that _____ was much lower in the bereaved people than in the controls.

A) lymphocyte functioning
B) neurotransmitter activity
C) antigen replication
D) ion activity