Science — CBSE Class 10 board question

(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A). The brain sends messages to muscles via the nervous system for voluntary actions; the PNS definition is a separate fact.

• A is true: The textbook states that for actions like writing and talking, "the brain also has to send messages to muscles" — this is the second way the nervous system communicates with muscles.
• R is true: The textbook explicitly states "the peripheral nervous system consisting of cranial nerves arising from the brain and spinal nerves arising from the spinal cord."
• R does NOT explain A: The PNS definition (R) merely names the components; it does not explain why or how the nervous system communicates with muscles during voluntary actions. Hence option (B).