Answer:
2) environmental influence on gene expression.
Explanation:
A body of a person has the ability to increase in height due to the genetic makeup but the person did not attained the height due to improper uptake of food that the requires, so due to the unavailability of food, the increase in height did not occur. This is due to the environmental conditions not the due to genetic makeup of the person. If the person eats food with sufficient nutrients, increase in height will occurs.