| A | B |
|---|
| molting | the process of an arthropod shedding its exoskeleton |
| joint | a plce where 2 or more parts of a skeleton meet |
| muscle | tissues that contract or relax to create movement |
| nervous system | a system that receives signals from the environment and reponds to them |
| stimulus | a signal that causes a response |
| response | the reaction to a stimulus |
| neuron | a nerve cell that carries electrical signals |
| impulse | an electrical signal in a neuron |
| sensory neuron | nerve cells that detect stimuli |
| interneuron | nerve cells that relay information between sensory neurons and motor neurons |
| motor neuron | nerve cells that activate muscles and other organs |
| brain | an organ that consists of neurons that help and organism controlits movement and thought |
| watervascular system | a system of fluid-filled tubes that help someorganisms move and grip surfaces |
| swim bladder | a gas-filled sac that helps a fish control depth without swimming |
