Answer:
By being the located in an area that traders could reach in a single monsoon season.
Step-by-step explanation:
Kilwa became a very important city for trade. Around the thirteenth century, its fortifications and the flow of goods in the city were both increased, it seems. For that to be the case, many assume that the city most likely had some sort of political administration overseeing the movement of goods and taking care of the city.