The action of the immune system at day 5 is most likely in response to the introduction of
A. an antibiotic
B. an antibody
C. an antigen
D. an immunoglobulin
E. a major histocompatibility complex molecule
Answer: C. an antigen
The action of the immune system at day 5 is most likely in response to the introduction of
A. an antibiotic
B. an antibody
C. an antigen
D. an immunoglobulin
E. a major histocompatibility complex molecule
Answer: C. an antigen