Question

What organ systems do flatworms lack?

Answer 1

Flatworms

1. Any member of the phylum flatworm, commonly known as Platyhelminthes. Platyhelminthes are a class of invertebrates with soft bodies that are often quite flattened. There are many free-living flatworm species, but around 80% of all flatworms are parasitic, meaning they live on or in another creature and get their nutrition from it.
2. A flatworm's stomach only has one entrance, located in the center of its underbelly.
3. The pharynx (throat/mouth) of flatworms in vernal pools may pierce their prey. It sucks out the insides of its victim like a small suction tube. Additionally, they employ it to expel waste from their bodies.
4. Without a respiratory or circulatory system, flatworms absorb nutrients through the body wall to perform these tasks.
5. A simple, inadequate stomach characterizes nonparasitic forms; many parasitic organisms lack even this.
6. Some flatworms have longitudinal, circular, and oblique muscle layers that regulate movement.