Final answer:
The presence of the River Nile made Nubia suitable for settlement due to its consistent water source, fertile soil, and annual flooding.
Step-by-step explanation:
The natural feature that made Nubia suitable for settlement was the presence of the River Nile. The Nile River provided a consistent water source for irrigation and agriculture, leading to fertile soil that was ideal for farming. The annual flooding of the Nile also brought nutrient-rich sediment which further enhanced the fertility of the land.