What is the correct sequence of components in a withdrawal reflex arc?
A
Option A: Sensory neuron → receptor → motor neuron → effector → relay neuron
B
Option B: Effector → motor neuron → relay neuron → sensory neuron → receptor
C
Option C: Receptor → motor neuron → relay neuron → sensory neuron → effector
D
Option D: Receptor → sensory neuron → relay neuron → motor neuron → effector
Correct answer D. Receptor → sensory neuron → relay neuron → motor neuron → effector
Explanation
A stimulus at the receptor sets up impulses in the sensory neuron. These pass via a relay neuron in the spinal cord to a motor neuron, which activates the effector muscle.
Answer checked 11 October 2026 · How we write and check questions
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