Passage:
For decades, paleoanthropologists maintained that the invention of controlled fire was the single catalyst that allowed early hominins to expand into colder, high-latitude Eurasian environments during the Early Pleistocene. Proponents of this "thermal adaptation" hypothesis pointed to burnt bones and ash deposits found at hearth sites in temperate zones as proof that survival without artificial heat was physiologically impossible. However, recent micro-stratigraphic analyses of early European cave sites reveal that hominin occupation layers during glacial periods frequently lack any trace of combustion residue or charcoal. Instead, stone tool cut marks on fossilized ungulate remains indicate that these early populations relied heavily on high-calorie animal fats and dense mammalian hide clothing to maintain thermal homeostasis. Far from being an indispensable prerequisite for northern migration, controlled fire appears to have been adopted opportunistically long after hominins had already established permanent settlements in frigid climates.
Based on the passage, the author references the "burnt bones and ash deposits" primarily in order to:
- describe the evidence previously relied upon by proponents of the view that fire was essential for hominin survival in cold climates.Answer
- Bassert the author's primary claim that early hominins mastered fire technology immediately upon migrating into temperate zones.
- Cpresent a factual finding that conclusively demonstrates early hominins could not survive without artificial heat.
- Dhighlight the micro-stratigraphic evidence used by recent researchers to disprove the thermal adaptation hypothesis.