What type of organism typically exhibits a nerve net?

The correct answer is that cnidarians typically exhibit a nerve net. Cnidarians are a group of simple aquatic animals that include jellyfish, corals, and sea anemones. They possess a decentralized network of nerve cells, known as a nerve net, which is spread throughout their body. This nerve net allows them to coordinate simple movements and respond to environmental stimuli without a centralized brain. The structure of the nerve net enables these organisms to react to touch and other sensory information, facilitating their survival in aquatic environments.

In contrast, mammals, fish, and insects possess more complex nervous systems with centralized brain structures and spinal cords that allow for advanced motor control, sensory processing, and behavioral responses. Their nervous systems are organized differently, which is primarily a reflection of their evolutionary complexity and the specific demands of their environments.