<P> Arabinoxylans are found in both the primary and secondary cell walls of plants and are the copolymers of two sugars: arabinose and xylose . They may also have beneficial effects on human health . </P> <P> The structural components of plants are formed primarily from cellulose . Wood is largely cellulose and lignin, while paper and cotton are nearly pure cellulose . Cellulose is a polymer made with repeated glucose units bonded together by beta - linkages . Humans and many animals lack an enzyme to break the beta - linkages, so they do not digest cellulose . Certain animals such as termites can digest cellulose, because bacteria possessing the enzyme are present in their gut . Cellulose is insoluble in water . It does not change color when mixed with iodine . On hydrolysis, it yields glucose . It is the most abundant carbohydrate in nature . </P> <P> Chitin is one of many naturally occurring polymers . It forms a structural component of many animals, such as exoskeletons . Over time it is bio-degradable in the natural environment . Its breakdown may be catalyzed by enzymes called chitinases, secreted by microorganisms such as bacteria and fungi, and produced by some plants . Some of these microorganisms have receptors to simple sugars from the decomposition of chitin . If chitin is detected, they then produce enzymes to digest it by cleaving the glycosidic bonds in order to convert it to simple sugars and ammonia . </P> <P> Chemically, chitin is closely related to chitosan (a more water - soluble derivative of chitin). It is also closely related to cellulose in that it is a long unbranched chain of glucose derivatives . Both materials contribute structure and strength, protecting the organism . </P>

Which of these is an example of a polysaccharide