D. It prevents harmful substances from entering the cell. I am very confident in this answer. The cell membrane is selectively permeable, and its job is to let certain things in and to keep certain things out.
<span>Children who suffer from Tay-Sachs disease have the inability to break down certain lipids in the body. The lipids accumulate in the brain and interfere with normal biological processes.</span>
I think it is because in the ocean the plankton produces most of the oxygen which is used by aquatic plants and plankton is a primary producer known as autotrops.
