-------------------------------------Passive Transport---------------------------------------------------
In passive transport, substances move across the cell membrane without the use of cellular energy. This process just happens naturally. It is important to remember, as mentioned before, that substances move naturally from a higher concentration to a lower one. Think of a crowded room. In these cases, the moment that the door opens and people are allowed to leave the crowded room for more space, they do so. Passive transport acts in the same way.
