Flatworms have a flat body because they lack a fluid-filled body cavity. They also have an incomplete digestive system with a single opening. … The mesoderm layer allows flatworms to develop muscle tissues so they can move easily over solid surfaces.

Why is it important for flatworms to be flat?

Structure and Function of Flatworms They have a flat body because they do not have a coelom or even a pseudocoelom. They also lack a respiratory system. Instead, their cells exchange gases by diffusion directly with the environment.

How is the shape of flatworms beneficial?

What do you notice about the shape of flatworms? How is this shape beneficial? Their shape allows the species to survive without a circulation system to deliver oxygen and remove waste from cells throughout the body.