Active transport vs Passive Transport....how to determine?
Well, look at the two words before "transport"...
Passive transport can be also called "diffusion", and happens when molecules move down a concentration, i.e. moving from a region of higher concentration to a region of lower concentration. This happens entirely due to the fact that all things in the universe want to move towards a chemical equilibrium. This does not require any energy to do.
Active transport on the other hand, requires energy, usually in the form of enzymes and
Here is a picture to differentiate between the two: