Final answer:
Cellulose is a polysaccharide and a major component of plant cell walls; it is indigestible by humans but crucial as dietary fiber. Herbivores digest cellulose with the help of symbiotic microorganisms that produce cellulase, converting cellulose into usable glucose for energy.
Step-by-step explanation:
Cellulose is a complex carbohydrate and a primary component of the cell walls of green plants; this substance is also referred to as dietary fiber when it is consumed by animals. Humans and some other animals cannot digest cellulose due to the absence of appropriate enzymes required to break the ß 1-4 linkage between glucose monomers. However, certain herbivores like cows, buffalos, and horses rely on a symbiotic relationship with microorganisms in their digestive system, such as bacteria that produce the enzyme cellulase, which allows them to utilize plant material rich in cellulose as a food source.
The symbiosis is critical for these animals because it aids in the digestion of cellulose, turning it into glucose monomers that provide energy. This relationship highlights the importance of symbiosis in the animal kingdom, especially among herbivores that must be able to extract necessary nutrients from plant-based diets.