Correct Option
The correct option is Both A and R are true but R is NOT the correct explanation of A.
Explanation
A reflex action is a sudden, involuntary, and automatic response to a stimulus, mediated by the nervous system. The neural pathway taken by the nerve impulses during a reflex action is called a reflex arc.
Statement-wise Analysis
- Assertion (A): Correct
Reflex arcs are formed in the spinal cord. In this process, sensory nerves detecting a stimulus connect with motor nerves (often via a relay neuron) within the spinal cord itself. This allows the signal to be processed at the level of the spinal cord before the information reaches the brain, ensuring a rapid response. - Reason (R): Correct
Reflex actions are defined as involuntary responses to peripheral nervous stimulation. They occur without conscious effort or thought (e.g., pulling a hand away from a hot object).
Relationship Analysis
While both statements are factually true, the Reason (R) does not correctly explain the Assertion (A). The reflex arc is formed in the spinal cord primarily to shorten the reaction time by bypassing the complex and slower thinking processes of the brain. The definition of a reflex as "involuntary" (R) describes the nature of the action but does not explicitly explain the anatomical necessity of the spinal cord location, which is driven by the need for speed.
Key Takeaway
Reflex arcs are located in the spinal cord to facilitate immediate action by bypassing the brain's thinking centers, although the information is eventually transmitted to the brain for memory and awareness.