Final answer:
Ruminants have a unique, multi-chambered stomach with four compartments: rumen, reticulum, omasum, and abomasum, which aids in digesting large amounts of plant material. This is in contrast to the human monogastric stomach, which has only one chamber. so, option 3 is the correct answer.
Step-by-step explanation:
The ruminant digestive system is adapted to efficiently digest large amounts of plant material. It consists of four compartments: the rumen, reticulum, omasum, and abomasum. The first two compartments, the rumen and the reticulum, are home to microbes that can break down cellulose fiber. Ruminants often regurgitate the partially digested feed known as cud from the reticulum to chew it again. After this, the cud moves to the omasum where water is removed, and finally to the abomasum, which functions as the true stomach, where digestion continues with the aid of enzymes.
Pseudo-ruminants have a three-chamber stomach with distinct parts, but they don't possess a rumen. Their large cecum plays a crucial role in breaking down cellulose. By contrast, the human digestive system is monogastric, possessing only one stomach chamber. Thus, ruminants have a stomach with four compartments, not a stomach similar to humans, nor a stomach with only three compartments.