Correct Answer: rumen

Solution : The correct option is rumen .

Bacteria in the rumen aid in the digestion of cellulose in ruminants, such as cattle. In ruminants, the rumen is the first region of the stomach. It is home to a diverse range of microorganisms, including fungi, bacteria, and protozoa, which are essential for the microbial fermentation process, which breaks down cellulose and other complex plant components. Ruminants can obtain nutrients from plant materials that would otherwise be indigestible thanks to this symbiotic connection.