Why is flatworms consdered to be more complex than hydra?

Flatworms are considered more complex than hydra due to their advanced body organization and internal systems. They possess a bilateral symmetry, which allows for a more defined head and tail region, and exhibit a more developed nervous system with a centralized brain. Additionally, flatworms have a three-layered body structure (triploblastic) and specialized organs for digestion and excretion, whereas hydra are simpler, radially symmetrical organisms with a two-layered body structure (diploblastic) and a less complex nervous system. This increased complexity in flatworms reflects their evolutionary advancement over hydra.