Final answer:
The matter in the spinal cord that contains functionally similar axons called tracts or fasciculi is white matter. White matter is composed mainly of myelinated axons of motor and sensory neurons.
Step-by-step explanation:
The matter in the spinal cord that contains functionally similar axons called tracts or fasciculi is white matter. White matter is composed mainly of myelinated axons of motor and sensory neurons. It forms a continuous band along the length of the spinal cord and carries sensory information up to the brain and motor commands from the brain.