Final answer:
The closed-panel plan restricts the enrollee to providers on the panel, but does not prevent new physicians or enrollees from joining. Enrollees can switch plans if allowed.
Step-by-step explanation:
The closed-panel plan is a type of health insurance plan where the enrollee is restricted to the providers on the panel. This means that the enrollee can only receive healthcare services from doctors and hospitals that are part of the plan's network. It does not prevent new physicians from being added to the plan, nor does it prevent new enrollees from joining the plan. Additionally, the enrollee can switch from one plan to another if allowed by the insurance provider.