Answer: It is necessary for the immune system to clearly distinguish foreign cells and proteins from those made by the body so that the immune system will be able to fight foreign cells and proteins and eliminate them from the body.
Explanation: The ability of the immune system to clearly distinguish foreign cells and proteins from those made by the body helps the body to identify pathogens that invade the body and trigger appropriate immune response to eliminate the foreign cells and proteins.
When the immune system of the body fails to distinguish foreign cells and proteins from those made by the body, the body launches an attack against its cells, that is the immune system triggers an autoimmune response in which attacks are launched against the cells of the body and destroy them. This condition in which the immune system recognizes the cells of the body as non-self and launches an attack against them is known as autoimmunity. Autoimmunity is the major cause of most degenerative diseases such as type I diabetes mellitus.
More commonly, an X chromosome will die and get replaced by a Y chromosome (all humans start off as females). When this occurs, the substitute Y chromosome causes changes in the zygote to occur; they begin developing male genitalia (i.e. penises, testicles, prostates, etc.).
Introducing a predator means there will be less prey which will help balance the population of prey. Some predators may run out of food and there might be no prey left for them. If the prey were removed the predator population would decline.
