Final answer:
In arthropods, segments combined into functional groups are called Tagmata. A bundle of axons in the peripheral nervous system is termed a nerve, while in the CNS, it is referred to as a tract.
Step-by-step explanation:
Groups of segments fused or combined into functional groups in arthropods are called Tagmata. The term for a bundle of axons in the peripheral nervous system is a nerve. In the central nervous system (CNS), such a bundle is referred to as a tract.
A localized collection of neuron cell bodies is known as a nucleus in the CNS and as a ganglion in the PNS. Morphological adaptations in arthropods led to body regions called tagmata which confer distinct functions such as sensing, moving, or feeding.