Skin is kept moist by the secretion of epidermal mucous gland cells and coelomic fluid.The given characteristic feature is a common respiratory adaptation in

Explanation

The correct answer is frog. Frogs have adapted to their environment by developing a moist skin that allows for cutaneous respiration, meaning they can absorb oxygen directly through their skin. This is a key feature of their respiratory system, especially when they are underwater or in moist environments.The option hydra is incorrect because hydras do not have a specialized skin for respiration; they rely on simple diffusion across their body surface.The option cockroach is incorrect as cockroaches use a tracheal system for breathing, which is entirely different from skin respiration.Although earthworm also uses moist skin for respiration, the mention of 'epidermal mucous gland cells' specifically aligns with the amphibian adaptation seen in frogs.