Final answer:
The statement is true; Homo erectus had smaller back teeth and relatively larger front teeth compared to australopithecines due to dietary changes and the use of fire.
Step-by-step explanation:
The statement that the back teeth of Homo erectus are smaller and the front teeth are relatively larger than those of an australopithecine is True. The evolutionary trend within hominins shows a progression towards smaller jaws and teeth. Australopithecines, like the Paranthropus genus, had larger molars suited to grinding tough plant material. As the Homo lineage progressed, with species like Homo erectus, there was a notable decrease in the size of the back teeth, attributed to changes in diet and the use of fire for cooking, which required less heavy chewing and thus less need for large molars. At the same time, there was a relative increase in the size of the front teeth and a reduction in prognathism, allowing more space for brain expansion.