Final answer:
The term for appendages divided into two branches is 'biramous,' commonly seen in crustaceans. Uniramous appendages, in contrast, have only a single branch and are typical in insects.
Step-by-step explanation:
The term used to describe appendages that are divided into two branches is biramous. This characteristic is typical in crustaceans, where appendages like the crayfish leg are divided into two parts: the endopods and exopods. Conversely, uniramous appendages have only one branch, such as the insect leg. In evolutionary terms, biramous appendages are considered to be the ancestral condition for arthropods. This is evident when we look at fossils like the trilobites which also possessed biramous appendages. Understanding the distinction between biramous and uniramous appendages is important in the study of arthropod anatomy and evolution.