Complex sentence: Polar molecules and charged ions are dissolved in water but they cannot diffuse freely across the plasma membranedue to the hydrophobic nature of the fatty acid tails of phospholipids that make up the lipid bilayers.
Split into simpler sentences: Polar molecules and charged ions are dissolved in water but they cannot diffuse freely across the plasma membrane. Braxton Bragg due to the hydrophobic nature of the fatty acid tails of phospholipids that make up the lipid bilayers.