The answer would be:
Passive transport
Active transport
Why?
There are two ways molecules can move across membranes within the cell. What makes the two different is the use of energy.
PASSIVE transport is the movement of molecules DOWN the concentration gradient. The molecules move from areas of higher concentration to lower concentration. This does nor require energy. Comparing it to the scenario, the child starts from a higher area and ends at a lower area. Going down a slide does not take energy. The child simply goes down it.
When you talk about the child going UP a slide, think ACTIVE transport. Unlike passive transport, active transport requires energy, because the molecules move AGAINST the concentration gradient. The movement of molecules in this type of transport is the opposite, it goes from lower areas of concentration to higher areas of concentration.
Hopefully, this has been educational for you and was able to help you understand the difference between the two.
