Whenever a germ or infection enters the body, white blood cells are the first to respond. They generally live from a few days to a few weeks. White blood cells are cells of the immune system, defending the body against pathogens and antigen. An antigen is a substance that prompts the generation of antibodies and can cause an immune response. White blood cells circulate in the blood so that they can be moved to an area where an infection has developed. There are six main types of white blood cells. Unlike red blood cells, white blood cells contain a nucleus and are larger than the red blood cells.
I know that's not quite ten sentences, but maybe it'll help get you started?? Hope I helped =) =)
P.S. No, I didn't just find some random article on the internet, copy, and paste it. I actually did some reasearch and looked on about ten different sites... Anyway good luck!
