Explain two ways the southwest used something from their environment in their culture. Please help please

1of the following choices, which one best describes one way that christianity came to east africa? a. christians traveled in caravans through the sahara desert and introduced the people of mali to a new religion. b. christian traders from the mediterranean interacted with the people of axum. c. christian military from west africa traveled across the continent to bring their religion to the people of east africa. d. christian rulers from asia traveled to east africa to bring their religion to the people. 2 which trade item from outside the region did west africans need most? a. gold b. camels c. salt d. iron