Which of the following is a principle of the fluid mosaic model of the plasma membrane structure?

The lipid bilayer is a solid at body temperature, thus protecting the cell.

All proteins associated with the cell membrane are contained in a fluid layer on the outside of the cell.

Phospholipids form a bilayer that is largely impermeable to water-soluble molecules.

Phospholipids consist of a polar head and a nonpolar tail made of three fatty acid chains.