Which of the following statements is false? a. lipids and many membrane proteins diffuse laterally in the membrane. b. sphingomyelin is a phospholipid with a glycerol phosphate backbone. c. a cerebroside containing sialic acid is referred to as a ganglioside. d. membrane fluidity is controlled by fatty acid composition. e. membranes are functionalized by proteins, i. e., proteins carry out most membrane processes.