the answer is unknown
Some animals have relatively short digestive tracts because they are carnivores. Herbivores need longer digestive tracts than carnivores in order to digest cellulose.
Mucous membranes line the digestive and respiratory tracts.
Mucus
incomplete
captain jack sparrow
It is called Endoderm
The Epithelium
The Epithelium
Everything except the urinary and digestive tracts.
visceral smooth muscle
pH of about 7, except for in stomachs and digestive tracts
Bacteria are technically living creatures that do not have any sort of digestive tracts. They do not have lysosomes, mitochondrion, etc.