Reflex arc sequence for blinking

Steps:

• Identify the reflex arc components: receptor detects stimulus, sensory neuron transmits signal, relay neuron processes in CNS, motor neuron activates effector.
• Match choices to this order: detection → sensory → relay → motor → response.
• Eliminate incomplete or reversed sequences in A, B, C.
• Confirm D follows full pathway from cornea receptor to eyelid muscles.

Why D is correct:

• It accurately describes the reflex arc pathway, per the biological definition: stimulus detection by receptor cells in cornea → sensory neuron → relay neuron → motor neuron → muscle contraction for blink.

Why the others are wrong:

• A: Incomplete and disordered, skips receptor and mixes neuron types.
• B: Fragments sensory impulses and omits relay/motor sequence.
• C: Starts with insect instead of receptor, lacks full neuron chain.

Final answer: D