According to the fluid mosaic model of the cell membrane,
a. there are fats floating in the protein layer.
b. carbohydrates function as membrane channels.
c. nonpolar ends of phospholipids are exposed to water inside and outside the cell.
d. protein molecules that perform important cellular functions float in a lipid bilayer.
e. there is a double protein layer in the plasma membrane.

According to the fluid mosaic model of the cell membrane, protein molecules that perform important cellular functions float in a lipid bilayer.

The most important biomolecules that form the cell membrane are lipids (especially phospholipids and cholesterol), proteins, and carbohydrates. The fluid mosaic model states that the cell membrane is a mosaic of biomolecules (which include lipids and proteins) that are constantly moving. Membrane proteins can be divided into two types: integral (intrinsic) and peripheral (extrinsic) membrane proteins The movement of these biomolecules enables the cell membrane to maintain its role as a selectively permeable barrier between  the extracellular environment and the interior of the cell.

In conclusion, according to the fluid mosaic model, proteins are essential components of the cell membrane that float in the lipid bilayer.  

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The answer is C. Nonpolar ends of phospholipids are exposed to watee inside and outside the cell