Self-preservation is a behavior or set of behaviors that ensures the survival of an organism. It is universal among all living organisms. For sentient organisms, pain and fear are integral parts of this mechanism. Pain motivates the individual to withdraw from damaging situations, to protect a damaged body part while it heals, and to avoid similar experiences in the future. Most pain resolves promptly once the painful stimulus is removed and the body has healed, but sometimes pain persists despite removal of the stimulus and apparent healing of the body; and sometimes pain arises in the absence of any detectable stimulus, damage or disease. Fear causes the organism to seek safety and may cause a release of adrenaline, which has the effect of increased strength and heightened senses such as