Coordination and response

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Across
  1. 2. Organs in charge of producing an effect
  2. 5. The maintenance of a constant internal environment
  3. 8. Where receptors are found
  4. 9. A change in an animal's surroundings
Down
  1. 1. A ... response requires a stimulus, receptor and effector
  2. 3. An organ that detects a change in the environment
  3. 4. Organisms are able to respond to changes in their ...
  4. 6. Tiny electrical signals that transmit information
  5. 7. A reaction to a change in surroundings