Final answer:
The fusion of adjacent body segments in arthropods to form specialized functional regions, known as tagmata, is referred to as tagmosis.
Step-by-step explanation:
The process of fusing adjacent body segments into a few specialized segments is called tagmosis. This biological concept is primarily observed in arthropods, where the fusion of adjacent groups of segments leads to the creation of specialized functional body regions known as tagmata.
Examples of tagmata include structures such as the head, thorax, and abdomen in various arthropods, which are the result of evolutionary processes that combined simpler ancestral segments into more complex ones. It helps in differentiating the distinct body regions with their respective functions, like sensing the environment, capturing food, or facilitating movement.