They are, just check out a sea fan or coral. B. General gut structure. Consider the problem of moving a golf ball through a garden hose. Oral Cavity Site of the initial stage of the digestion process. Saliva also has anti-microbial properties.
Food presses against soft palate initiates swallowing reflex.
Leads from pharynx to stomach. A. Gastric juices Produced by glands that line the epithelium. Pepsin is the active form, digests protein. Food lasts 2-6 hours in stomach. Pressure on the involuntary one causes it to open.