Worms do not have teeth. Organic matter is ground up in a worm's gizzard. Redworms are surface-dwellers, preferring the top six inches of soil. Nightcrawlers are soil-dwellers, and like to burrow several feet below the surface. There are approximately 3,000 species of earthworms named and known to science.
Earthworms are neither male, nor female, but both.
Each worm can produce eggs and sperm. Worms have no eyes, but they are sensitive to light. Don't add too much and strew it like you do with sugar on your corn flakes. Cover with bedding or you will get flies. Bread Coffee grounds makes the worms peppy.