Ascientist is comparing the outer layer of an onion cell to the outer layer of a human skin cell. what is unique about the outer layer of the onion cell compared to the skin cell?
a. it contains proteins.
b. it contains cellulose.
c. it contains carbohydrates.
d. it is selectively permeable.

b. It contains cellulose.

An enzyme is defined as a protein catalyst. Many enzymes consist of a protein, the apoenzyme,  and a non protein component known as a cofactor required for catalytic activity. The complete enzyme consisting of  the apoenzyme and its cofactor is called the holoenzyme. Cellulose is a polysaccharide made up of glucose units.Cholesterol is an organic compound made of lipids with a rather unique structure consisting of hydrocarbons.Starch is polysaccharide composed of amylose and amylopectin.