Why do historians need anthropologists and archaeologists to study prehistory?

Prehistory is the time before written records, so we could not study what happened then from written evidence. The only chance of finding out about the past is finding the remains of objects used by the people who lived then and interpret them, and to study the remains of the people themselves. This is the job of anthropologists and archaeologists. Through their work anthropologists and archaeologists tell us about the prehistory.