Well the flu is a virus. Knowing it’s a virus we know they multiply by entering a cell and passing over there rna then converted to be dna and creating other versions of them selfs until cytolysis occurs meaning the cell explodes with these new viruses and do the same with other cells. Since these dna conventions to create protein body parts of virus means there’s a increase in chemical reactions in the body and enzyme production. Also since your body has an immune system it can sense these antigens from the virus’s and cause increase in certain white blood cells to come in and kill these viruses and cells. In essence chemical and enzyme reactions increase. To survive.
