What does the second blue peak (around day 40) represent? What does the second blue peak (around day 40) represent? the peak of the secondary immune response to antigen Y the peak of the secondary immune response to antigen X the peak of the primary immune response to antigen X the peak of the primary immune response to antigen Y

B. The peak of the secondary immune response to antigen X

Explanation:

(See attachment for missing details)

The secondary immune response takes place when a person is repeatedly exposed to the same antigen. Getting to this stage, the immunological memory would have been setup and the immune system will immediately proceed to making antibodies.

From the attached, it takes the primary immune system 28 days to get to its peak and the secondary immune response is stronger than the primary immune response