Sensory neurons are responsible for receiving external stimuli and passing signals to the central nervous system. Which of the following best matches their role?

• A. Carrying signals from the brain or spinal cord to muscles or glands
• B. Receiving external stimuli from the environment and passing signals to the CNS
• C. Forming synapses with other neurons
• D. Producing neurotransmitters

Answer: (B)

Sensory neurons convey information from receptors that detect stimuli in the environment to the central nervous system. They pick up signals like touch, light, sound, temperature, and chemical changes and convert them into electrical impulses that travel toward the brain and spinal cord for processing. This directional flow—from the sensory receptors to the CNS—is exactly what this role describes, making it the best match. Signals that travel from the brain or spinal cord to muscles or glands are sent by motor neurons, not sensory ones. While forming synapses and producing neurotransmitters are general neuronal features, they don’t capture the specific job of detecting external stimuli and delivering that information to the CNS.