What characteristics make a hydra animal?

Hydra are small, freshwater organisms belonging to the phylum Cnidaria, characterized by their tubular body shape, radial symmetry, and the presence of specialized cells called cnidocytes that contain stinging structures called nematocysts. They possess a simple body plan with a mouth surrounded by tentacles, which they use for capturing prey. Hydras are notable for their regenerative abilities, allowing them to recover from injury or even reproduce asexually through budding. Additionally, they exhibit a form of simple nerve net for basic responsiveness to stimuli, distinguishing them as animals.