<em>Active transport</em><em> uses </em><em>cellular energy</em><em> to </em><em>move molecules</em><em> based on the </em><em>concentration level</em><em> and </em><em>Passive transport doesn't</em><em> require </em><em>energy</em><em> to </em><em>move molecules within</em><em> their </em><em>cells</em><em>.</em>
<u>EXPLANATION: </u>
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.
The period is the time it takes the satellite to make a complete orbit around the central object. As the distance increases, so does the period because the orbit becomes longer because the radius increases.
