Solution

Fluid mosaic model is the most recent and widely accepted model of a biomembrane which was proposed by Singer and Nicolson in $$1972$$. Fluid mosaic model describes cell membrane as quasifluid, i.e., 'protein icebergs in a sea of lipids'. According to this model, there is a bilayer of lipid molecules (phospholipid) with globular protein molecules $$(2$$ types - integral and peripheral) and sterols which are arranged in different manner in different regions of the plasma membrane. So, the correct answer is 'Quasifluid'.