The composition of a cell differs from that of the cell membrane in that the cell membrane is

The correct answer is mostly lipid while the whole cell is mostly aqueous .
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This is because the cell membrane is majorly composed of the phospholipid bilayer. It is a protective covering present in all the cells.  

On the other hand, the whole cell other than the cell membrane is mostly aqueous. It contains 80% of water, therefore considered as aqueous. It is also referred to as cytoplasm of the cell. Most of the cellular activity including metabolic processes and signaling pathways occur within the cytoplasm of the cell.

C. gemstones they are the only non metallic mineral from the list.