Full of wonder is one description that fits the nature of the human body. How a newborn, who had never been hungry, instinctively knows that feeding from his or her mother's breasts will satisfy his or her need, is one proof of the amazing design of the human body. Among other astounding pieces of evidence of such beauty is how the body is programmed to defend itself from danger internally, without you having to know it. Immunity is the condition in which there are adequate biological 'soldiers' in your body, in both in quality and in quantity. These defenses function to fight infection, illness, or other uninvited biological attack. It is also defined as the body's competence to protect itself from harmful microorganisms from getting into it.