Cellulose Is Not Digested by Humans Because It

Multiple Choice

Cellulose is not digested by humans because it

A) is a relatively insoluble protein-carbohydrate complex inaccessible to digestive enzymes.
B) is a mucopolysaccharide, which is not a substrate for digestive enzymes.
C) is highly sulfated, making it inaccessible to the action of most glycosidases.
D) is a polymer of glucose molecules in beta 1-4 linkage for which we have no digestive enzymes.
E) resists enzyme action due to its highly branched structure.