The correct answer is:
The Bantu brought advanced iron tools and new crops such as cereal grains to the new regions they settled.
With their advanced iron tools, the Bantu were able to clear larger areas of land for agriculture and cultivate crops more efficiently. They introduced new farming techniques such as slash-and-burn agriculture, which involves cutting down and burning vegetation to clear land for planting. This method allowed them to replenish the soil's fertility and grow crops successfully. Additionally, the Bantu brought new crops such as cereal grains, including sorghum and millet, which played a significant role in their diet and agricultural practices. These changes in farming techniques and introduction of new crops contributed to increased agricultural productivity and sustainability in the regions the Bantu migrated to.