Which of the following constituents of the plasma membrane enables the lateral movement of proteins within the overall bilayer? 

Lipids are amphipatic in nature, as they have a hydrophilic tail and hydrophobic head. As a result, they form a bilayer in the aqueous phase. Phospholipids, being the major constituents of the plasma membrane, form a lipid Bilayer and enable the lateral movement of proteins within the overall bilayer.