The process by which organisms maintain constant internal conditions if referred to as

The process by which organism maintain constant internal condition is referred to as HOMEOSTASIS.
Without the right body condition, certain processes and enzymes will not be able to function normally and this can be very fatal for the organism.
For instance, if the temperature is raised above some value, some enzymes in the body will be denatured and will not be able to carry out their functions, this will lead to disruption in the biochemical process of the body.

Giga is the second highest prefix on the normal scale, the first is terra.