The Major Difference Between the Cell Walls of Gram-Positive and Gram-Negative

The major difference between the cell walls of gram-positive and gram-negative bacteria is that

A) the peptidoglycan layer in gram-positive bacteria is substantially thicker.
B) the cell wall of gram-positive bacteria contains mycolic acids.
C) gram-positive bacteria contain a cytoplasmic membrane.
D) gram-positive bacteria may have a polysaccharide capsule as a covering.
E) All of the above are correct.