IGCSE Biology – Coordination and Response Practice Test

Understanding how information travels from sense organs to the CNS is being tested here. The signal from a sense organ is carried to the brain or spinal cord by a sensory neuron, which transmits the impulses toward the CNS for processing. A motor neuron, on the other hand, carries commands from the CNS to muscles or glands to cause a response. A receptor detects the stimulus but does not itself transport the impulse to the CNS, and an effector is the organ that carries out the response. So the sensory neuron is the correct choice.