Final answer:
All of the listed characteristics are true for facilitated diffusion, where molecules pass through membranes via protein channels, with specificity, dependency on gradients, and a saturable rate.
Step-by-step explanation:
The characteristic of facilitated diffusion (passive transport) of a molecule across a membrane that is correct is (E) All of the above are true. Facilitated diffusion is a process where molecules move across cell membranes through protein channels or carriers. It is indeed highly specific for the molecule being transported, and its rate can exceed simple diffusion due to the efficiency of transport proteins. Moreover, the direction of transport is dependent on concentration and/or electrochemical gradients, and the rate of transport is saturable, similar to enzyme catalysis behavior.