Many worms regenerate, this means to re-grow. If a worm loses part of its body because it's cut off or caught on something, the worm can grow that part back and still stay alive. Earthworms burrow tunnels into the ground the burrowing does something called "aerate" the soil. Aeration means putting air into the soil. This process is important to make sure that the soil uses all of the minerals it has available. That's why earthworms help gardens grow.