Which of these parts of the cell membrane are nonpolar and keep cells separate from water? a. the phosphate groups b. the membrane surfaces c. the fatty acid chains d. the membrane proteins

 Phospholipids- are membrane lipids designed with a hydrophilic(water-loving) head and a hydrophobic(water-fearing) tail end.  This is important because it allows these lipids to form important biological barriers, such as cell membranes. The cell membrane is formed via a phospholipid bilayer; meaning that there are two layers of phospholipids pointing in opposite direations. The polar heads face the inside and outside of the cell while the water-fearing tails are sandwiched in between the polar heads to be kept away from the watery environments.Therefore, Phospholipids are responsible for keeping things from entering the cell. The non-polar part of the phospholipid is its fatty acid tail. 

My C. The fatty acid chains

Hope this helped!

The right answer is c.sandstone.