____________ blood cells are responsible for the defense system in the body. like red blood cells, these cells are formed from the stem cells of the ____________ . the different types of these cells have life spans from hours to ____________ . approximately 5 to 10 ____________ of these cells are found per microliter of blood. their function includes defense of the body against infection. these cells use the process of ____________ to leave the circulation and move toward areas of infection or inflammation. they move about within the interstitial fluid by the process of ____________ motion.