Final answer:
The direct interaction region includes the process steps involving interaction between participants in a process chain.
Step-by-step explanation:
The region of a process chain that includes the process steps involving interaction between participants is the direct interaction region.
In this region, participants directly interact with each other to carry out the tasks required in the process chain.
For example, in a customer service process chain, the direct interaction region would include the steps where the customer interacts with the customer service representative to resolve their issue.