Final answer:
The third step in a traditional reflex arc is Integration of sensory input, where the sensory information that has entered the central nervous system is processed.
Step-by-step explanation:
The third step of five in a typical reflex arc is Integration of sensory input.
A reflex arc is a neural pathway that controls a reflex action. The process begins with the sensory receptor stimulating a response to a sensation.
This impulse travels along a sensory nerve to the spinal cord, where integration occurs.
This means the sensory input is processed and an appropriate response is formulated.
Following this, a motor neuron transmits the response to an effector organ, such as a muscle, which then reacts accordingly.
The sequence goes as follows: Sensory receptor stimulation, transmission to the CNS, integration of the sensory input, motor neuron response, and finally, the effector organ reaction.