Not to be confused with hemostasis. Homeostasis or homoeostasis (homeo- + -stasis) is the property of a system in which variables are regulated so that internal conditions remain stable and relatively constant. Examples of homeostasis include the regulation of temperature and the balance between acidity and alkalinity (pH). It is a process that maintains the stability of the human body's internal environment in response to changes in external conditions.
Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to something in the environment that usually causes little problem in most people.
A. Allergy is the exaggerated and out-of-place reaction of the immune system to external substances or stimuli that are not harmful to the body, so the reaction actually damages the body instead of helping it. The may be pollen and foods, as well as insect stings, drugs and almost any other substances.