What two items were most important in the Indian Ocean trade during the post classical period

These included Kilwa, Sofala, Mombasa, Malindi, and others. The city-states traded with inland kingdoms like Great Zimbabwe to obtain gold, ivory, and iron. These materials were then sold to places like India, Southeast Asia, and China. These were Africa's exports in the Indian Ocean Trade.

Explanation: Hope this help :)

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)

i am pretty sure it is a