Immunity is

your body's ability to destroy pathogens that is has previously encountered before the pathogens are able to cause disease.
white blood cells
your body's general response to injury
the ability to produce red blood cells

Immunity is your body's ability to destroy pathogens that it has previously encountered before the pathogens are able to cause disease. This is typically achieved through the action of white blood cells, which play a critical role in the immune system. Immunity is not directly related to the production of red blood cells, which are primarily responsible for carrying oxygen throughout the body.