Genes establish a of potential expression, and environment determines where a person's phenotype will fall within this.

The answer is: Reaction range

Reaction range refers to a concept that stated the phenotype that exist in organisms' genetic material would be adapted to the environment around them.  For example, birds that born in colder environment typically have thicker feather that can help to protect them from the harsh cold temperature compared to the birds that were born in warmer climate.