Aristotle was unsure whether or not sponges were animals, which in his program ought to have feeling, urge for food, and locomotion, or crops, which didn't: he realized that sponges could feeling touch and would deal if going to be pulled off their rocks, but they ended up rooted like vegetation and by no means moved about.[a hundred and fifty five

A digestive system with specialized organs, such as a belly and intestines, for breaking down mealsA fancy nervous technique, which has a spinal twine along with a brain that coordinates sensory enter and motor outputThe Ctenophora and Cnidaria are radially symmetric and have digestive chambers with a single opening, which serves as both equally mo