Final answer:
Unipolar neurons begin as pseudounipolar neurons during their development, which later branch into two parts, allowing them to receive and transmit sensory information.
Step-by-step explanation:
Unipolar neurons start out as pseudounipolar neurons during development. Initially, they have a single process that emerges from the soma, which later branches into two parts resembling the structure of bipolar neurons. This design allows pseudounipolar neurons to connect their dendrites to sensory receptors and transmit signals through their axons to the central nervous system. Unlike pure unipolar neurons found in invertebrates, which have a single structure extending from the soma and do not have dendrites, the pseudounipolar neurons found in humans have split axons that serve both as sensory input conduits and pathways to the central nervous system.