Worms Easier - A worm is an long, thin animal that lives in the soil. They have a soft, long, rounded body and no legs or backbone. Harder - There are thousands of different kinds of worms. The largest species measure many feet or meters long, while the smallest worm cannot be seen without a microscope.
Many worms eat small plants and animals, others feed on decaying matter.
Still other types of worms live as parasites in various animals and plants causing a number of diseases. Most types of worms have a well-developed sense of touch. They also have specialized organs that respond to chemicals in their surroundings. Many species have a sense of sight, with eyes or eyespots on the head. People mistakenly believe that caterpillars and grubs are worms.