Final answer:
The proto-Bantu people spread across Africa in a gradual and protracted migration, bringing their knowledge of ironworking and farming practices.
Step-by-step explanation:
The proto-Bantu people spread across Africa in a gradual and protracted migration that began around the first millennium BCE. This movement was not an invasion but a spontaneous expansion. The reasons for their spread are not entirely clear, with some scholars suggesting overpopulation, disease, or climate changes as possible factors.
As the Bantu people migrated, they brought with them their knowledge of ironworking, which allowed them to make better tools and weapons. This enabled them to clear land for farming and establish new settlements. The original populations of the areas they settled either assimilated into the Bantu population or moved to more remote locations.
The Bantu migrations had a significant impact on the linguistic and cultural landscape of Africa, spreading their Bantu languages and introducing farming practices to new regions. They also displaced and integrated with existing hunter-gatherer communities along their path.