How did Swahili help East African trade?

Swahili city-states also manufactured goods for both their own residents and for trade such as pottery, cloth, and highly decorated siwa, the typical brass trumpet of the region. Goods from Africa included: Precious metals - gold, iron, and copper. Ivory.

Explanation:

b because thats the naswer i got

answer; the sound of a train whistle makes a woman think of an old friend; //

the smell of grass makes a by feel that spring is the best; (apex);