The answer is 251.0 Hope I helped
Designing efficacious norovirus vaccines remains a major challenge due to several factors:
(1) the extreme genetic variability within the norovirus family and within genogroups
(2) the rapid evolution of antigenically dissimilar pandemic GII.4 norovirus strains
(3) the lack of lasting immunity upon natural exposure to noroviruses in at least a proportion of the population.
Artificial active immunity. I'm a bio major, hope I helped :)
Difference of heating.
HOped that helped :))
