Key Features of Biological Membranes Are

Key features of biological membranes are

A) the two sides appear to be indistinguishable in most membranes.
B) lipids rotate about their long axis and also move laterally in the membrane.
C) lipid molecules flip readily from one side of the membrane bilayer to the other.
D) the protein to lipid ratio of membranes is very close to 1:1 in almost all physiologically important membranes.
E) none of the above is true.