Final answer:
The rumen is the primary site of microbial fermentation in ruminant animals, where microbes break down cellulose and ferment plant material.
Step-by-step explanation:
In ruminant animals, such as goats and cows, most microbial fermentation takes place in the rumen. The microbes in the rumen break down cellulose and ferment the ingested plant material. This process is essential for the digestion of plant-based diets, which is why the ruminant's digestive system is uniquely adapted with multiple stomach chambers. After the rumen, the food passes into the reticulum and then the omasum, which functions more as a strainer and removes water. Finally, the food enters the abomasum, also known as the true stomach, where digestive enzymes are secreted to further break down the food matter.