Worms are a diverse group of invertebrates that belong to various phyla, including Annelida, Nematoda, and Platyhelminthes. These animals are characterized by their long, slender bodies and lack of limbs. Worms can be found in a wide range of habitats, including soil, freshwater, and marine environments, and play important roles in nutrient cycling and soil health. They are also used as a food source for many animals and are sometimes kept as pets.