Cnidarians are an example of organisms that possess a simple type of what system, used for sensing touch?
bacterial system
circulatory system
lymphatic system
nervous system
Cnidarians have a simple nervous system. It consists of a net of nerves that can sense touch. You can see a sketch of the nerve net in a hydra in Figure below . Some cnidarians also have other sensory structures. For example, jellyfish have light-sensing structures and gravity-sensing structures.