Final answer:
The wolf has a monogastric digestive system most similar to that of a human, with a single stomach and an extended small intestine suited for digesting meat, contrasted with the cow's ruminant system and the jellyfish's incomplete system.
Step-by-step explanation:
The animal with a digestive system most similar to a human is the wolf. Like humans, wolves have a monogastric digestive system with a single stomach and an extended small intestine, which is efficient for digesting a diet that includes meat. This contrasts with the cow, which has a ruminant digestive system with multiple stomach compartments, and the jellyfish, which has an incomplete digestive system with a single opening that serves as both mouth and anus. Octopuses also have a single stomach but have different digestive processes adapted to their unique diets and habitats.
To further dissect the comparisons, the cow, being a herbivore, has a more complex gut to allow for the digestion of cellulose from plant material, which requires specialized compartments like the rumen for fermentation. Jellyfish have a simple gastrovascular cavity, while wolves, similar to humans, break down food through a completely different mechanism involving a more complex system that includes organs such as a liver and pancreas, which assist in digestion and absorption of nutrients.