Question

where is a reflex arc formed

Answer 1

a reflex arc is formed at the point where the sensory neurons meet the relay neurons first on their way to the brain. Actually in a reflex action the electric impulse does not have time to reach brain, get the command and effect the movement of muscle ...AS THIS WOULD TAKE A LOT OF TIME.... so the sensory neurons meet with the relay neurons at the spinal cord. And hence the reflex arc is formed at the spinal cord..

Answer 2

Reflex action takes place through reflex arc.
A typical reflex arc consists of three types of neurons sensory neuron,motor neuron and relay neuron.
Reflex arc is formed in spinal cord .Though the message reaches the brain the action is spontaneous as the spinal cord brings about the action.
Hope this will help you! !!