What term describes the interplay that occurs when the effect of one factor, such as environment, depends on another factor, such as heredity?

The term that describes the interplay between factors like environment and heredity is "interaction." This concept highlights how the influence of one factor can vary depending on the presence or level of another factor. For example, the way an individual develops certain traits can be significantly affected by both genetic predispositions and environmental influences. In psychology, this notion is crucial for understanding how behavior and personality are shaped, as it acknowledges that genes do not operate in isolation but rather in conjunction with external influences.

In contrast to interaction, epigenetics focuses on how environmental factors can change gene expression without altering the underlying DNA sequence, helping to explain changes observed in traits or behaviors. Genetics specifically pertains to the study of heredity and the roles genes play in inheritance but does not encapsulate the complex relationships between genes and environment. Phenotype refers to the observable characteristics of an individual, which result from the interaction of their genotype with the environment, but it doesn't specifically define the relationship dynamic itself.

Therefore, interaction is the broad term that effectively captures the essence of how these various factors coexist and impact development and behavior.