The correct answer is option 4 - "no eyes." Earthworms do not have eyes. Unlike some other animals, earthworms do not rely on vision to navigate their environment. Instead, they have specialized light-sensitive cells called photoreceptors that can detect changes in light intensity. These cells help earthworms avoid light and stay underground, which is their preferred habitat. Earthworms rely mainly on their sense of touch and their ability to detect chemicals in the environment to find food, mates, and avoid danger. While earthworms may have other sensory organs, such as sensory bristles, they do not possess true eyes.