What is cellulose? (3 + 2 examples)

Polysaccharide (structural) found in the cell wall of plants linear molecule made of beta glucose in a 1-4 arrangement b glucose is indigestable to most animals as they lack the enzyme to break it down eg: cows (ruminants) digest cellulose because of bacteria in a specialized stomach eg: rabbits (caecotrophs) will reingest specialized feces that have digested cellulose