incomplete
They have complete digestive system.
planaira
platyhelminthes
platyhelminthes
platyhelminthes
Mammals have a complete digestive tract, it starts from mouth to anus. Although each species have some different type and length of tract, they have esophagus, ventriculus, intestinum which function to support a complete food metabolism. Besides, some digestive glands also support this function.
The crayfish digestive tract is complete. It consists of a mouth, esophagus, stomach, and intestine, allowing for the digestion and absorption of nutrients from food. The waste is eliminated through the anus.
A digestive system with only one opening is called an incomplete digestive tract. Organisms with this type of digestive system ingest food and eject waste through their mouth.
Leeches have a complete digestive tract. Leeches are members of Phylum Annelida. This phylum has the general characteristic of having a complete digestive tract, i.e. food goes in through the mouth, pass through digestive tract of some sort like stomach and/or intestine, waste gets discarded through some sort of rectal opening, i.e. anus. In comparison, an incomplete digestive tract generally means food goes in and waste come out of the same opening, i.e. mouth=anus. Lower level invertebrates have incomplete digestive tract like Phylum Cnidaria and Phylum Platyhelminthes members.
The anus is the last part of the digestive tract.
That wavelike movement of the digestive tract is known as peristalsis.