Ecdysozoa is a major group in the animal kingdom that includes organisms that undergo molting, a process known as ecdysis. This group primarily consists of arthropods, such as insects and crustaceans, and nematodes, or roundworms. These animals are characterized by having a tough outer cuticle that they shed periodically to grow. The Ecdysozoa are diverse and can be found in various habitats, from oceans to forests. They play essential roles in ecosystems, including serving as pollinators, decomposers, and prey for other animals. Their unique molting process allows them to adapt to changing environments and contributes to their evolutionary success.