Final answer:
Cellulose is the indigestible complex carbohydrate found in plant cell walls. Animals like humans cannot digest cellulose as they lack the necessary enzymes, thus it serves as dietary fiber which aids digestion and confers other health benefits.
Step-by-step explanation:
The indigestible complex carbohydrate found in the cell wall of plants is cellulose. Cellulose is a key structural component of plant cell walls and is composed of long chains of glucose units. However, animals like humans do not produce the enzymes necessary to digest cellulose, hence it passes through our digestive system undigested, where it provides health benefits such as improving bowel movements and giving a feeling of fullness.
Despite the abundance of cellulose in the environment, due to it being the most prevalent carbohydrate in the vegetable kingdom and a major component of paper and textile production, its indigestibility in certain animals, including humans, categorizes it as dietary fiber. This dietary fiber is essential in our diet as it aids digestion and can help to reduce the risk of certain diseases.