Viral infection will provoke cell mediated immunity but will not activate a humoral response.
a. true
b. false

This statement is false.  The humoral immune system is one part of the immune system that is activated when pathogens are present in the blood stream or other body fluids. B cells are the main cells involved in the response, and these cells secrete antibodies that seek out and attach to pathogenic molecules. These attached antibodies act as markers, marking the pathogens for destruction by other parts of the immune system.

Crossing over creates new combinations of genes in the gametes that are not found in either parent contributing to genetic diversity