Final answer:
Diego's development demonstrates the interaction between his genetic disposition and environmental influences that encourage his sociability.
Step-by-step explanation:
Diego's natural predisposition to be outgoing and friendly, and the way his environment appreciates and encourages these traits, exemplifies the strong interaction between genes and the environment.
The particular term that describes Diego's development into an extroverted and sociable person due to the interplay between his innate characteristics and his life experiences is interaction. This term captures the essence of the range of reaction theory and genetic environmental correlation, explaining how an individual's genetic predispositions are expressed and shaped by environmental influences, and vice versa.