If you are going from a high gradient to a low gradient it’s passive transport. Think of a hill if you put a rock at the top of that hill it will go down no energy involved. Active transport is going up the hill you must use energy to push that rock up the hill because it’s from a low gradient to the top. Hope this helps
Hydrophobic is when it cannot dissolve in water and hydrophilic is when it can. an example is a phospholipid in the cell membrane- the the tails are hydrophobic and the heads are hydrophilic.
