Soooo... thanks for the free points. Also I really need brainliest please
Answer:
Cells do not generally allow such materials to go in because they are having a cell membrane outside. The cell membrane only allows the materials which are required for the growth of the cell such as water and minerals.
<em><u>A.SURFACE </u></em><em><u>RUNOFF</u></em><em><u> </u></em><em><u>FROM </u></em><em><u>RAIN.</u></em>
<em><u>C.MELTING</u></em><em><u> </u></em><em><u>ICE</u></em>
<em><u>B.OCEAN </u></em><em><u>CURRENTS </u></em><em><u>(</u></em><em><u> </u></em><em><u>I </u></em><em><u>guess?</u></em><em><u>)</u></em>
<em><u>[that's it]:)</u></em>
What do you mean by responsible? Do you want to know the genetics behind it, what the surface markers do, or why they are metically important? I think I can help.
