Question

Cellulose is indigestible to most animals because

Answer 1

Humans lack cellulase , an enzyme that acts to decompose cellulosic material.Humans also have lost the cellulase producing bacteria to evolution oiver the time.Most mammals have only very limited ability to digest dietary fibres such as cellulose by themselves. In many herbivorous animals such as ruminants like cattle and sheep and gut-fermenters like horses, cellulases are produced by symbiotic bacteria....

Very few amphibians and reptiles can produce cellulase