Active and Passive Transport

Some things require energy in order to move into the cell. Other thinks do not require energy. Can you explain why? If not, here is a helpful demonstration. Remember, if you cannot explain the processes and meanings of active and passive transport (without looking at your book), then you dont truly understand it. Once it makes sense to you, simply revisit this page, or write it on paper a couple of times. This will make for inevitable retention of the concepts.