How do flatworms breathe without specialized respiratory organs?

Flatworms do not possess specialized respiratory organs, such as gills or lungs, to facilitate gas exchange. Instead, they rely on the process of simple diffusion, where gases move directly across their body wall. This method is effective for these organisms because they are soft-bodied and typically much flattened, which provides a high surface-area-to-volume ratio that supports the necessary exchange of oxygen and carbon dioxide with their environment.12