An unchanging, biologically inherited behavior pattern.
-personality
-heredity
-instinct
-sociobiology
-aptitude
-self

The answer is instinct.

Explanation:

Instinct is the spontaneous reaction in the behavior of an animal (or human being). Therefore, it is a behavior that is not the result of learning. It is then defined as an innate, stereotyped and specific behavior that is triggered by certain types of stimuli. Instinct is primarily hereditary and is not learned. Thus, it is common to an entire species. Instinct generates behaviors that are of great importance for survival. It is the instinct that allows subsistence, the relationship with the environment and with other individuals of the same species.

a 2,000 calorie based diet.