Final answer:
In a closed container, the dynamic equilibrium between a liquid and its vapor is characterized by constant pressure, where vaporization and condensation rates are equal.
Step-by-step explanation:
The feature that characterizes the dynamic equilibrium between a liquid and its vapor in a closed container is b) Constant pressure. At equilibrium, the rate at which the liquid becomes the gas equals the rate of gas molecules entering the liquid. This equilibrium is dynamic because vaporization and condensation occur at equal rates. The pressure exerted by the vapor in equilibrium with the liquid, also known as the vapor pressure, remains constant as long as the temperature doesn't change. The fact that vaporization and condensation are continuous processes is essential to the concept of equilibrium.