Active transport uses cellular energy to move molecules based on the concentration level and Passive transport doesn't require energy to move molecules within their cells.
EXPLANATION:
Active transport uses cellular energy for this movement. It uses energy stored in ATP to begin the transport. This means that the molecules transfer from an area where it is less in number to an area with a high concentration of molecules.
But Passive transport specifies the movement of molecules across cell membranes which doesn't require energy as it depends on the cell membrane's penetrability. Molecules just have to circulate in or out of the cell.