Answer: Termites and herbivores.
Step-by-step explanation:
The two organism that can digests cellulose are termites and herbivores. The termite contains protists known as mastigophorans carry out digestion of cellulose in the body.
The cellulose in this case is digested and prevents it from getting deposited in the environment.
The other organism are animals like ruminants which can digest cellulose in their gut. They partially digest the cellulose and regurgitate it into the mouth an broken down further.
This process of digestion of cellulose in the gut is anaerobic so methane is released in the environment as a product of digestion.
The human beings cannot digest cellulose and a very less amount of it is considered as fiber and is simply excreted.