Final answer:
The Swahili coast city-states used the predictable monsoon wind patterns to their advantage, powering their dhow ships for trade and navigation, which catalyzed their growth as central trading hubs in the Indian Ocean.
Step-by-step explanation:
The Swahili coast city-states took advantage of wind patterns in the Indian Ocean by using the winds to power their boats, allowing them to travel long distances. The monsoon winds in the area were predictable and seasonal, which facilitated a flourishing trade network between the city-states and other regions such as Arabia, Persia, and India. In the summer, the winds blew northeast toward the coast of India, perfect for trading vessels leaving Africa, and in winter, the winds reversed, enabling ships to return to Africa loaded with goods. This strategic use of wind patterns greatly contributed to the prosperity and growth of the Swahili coast as a major hub in the Indian Ocean trade. It allowed the city-states to import and export a variety of commodities, including gold, ivory, and enslaved Africans. The dhow, the region's standard ship, was a principal factor in harnessing these wind patterns, with its lateen sail design allowing efficient navigation with and against the wind.
However, these city-states did not extend along the entire African coast because the seas were too rough for the dhows and the monsoon winds grew weaker the farther south they went. Consequently, this geographic and climatic limitation helped shape the precise extent of the Swahili city-states' influence along the East African coast