Final answer:
A defined benefit plan's characteristic is that contributions are determined by a formula within the plan, ensuring a fixed benefit upon retirement without employee investment risk.
Step-by-step explanation:
A characteristic of a defined benefit plan is that the contributions are determined by a formula in the plan. These contributions are not commingled funds, and employees do not assume the investment risk as the employer promises to pay a certain benefit upon retirement, often based on factors like salary and years of service. Traditional private company pensions are examples of defined benefit plans, where retirees receive a fixed income that does not necessarily increase with inflation, potentially eroding purchasing power over time.