What does primitive mean as its used in paragraph 9

Rank the following from most to least devasting: ordovician,permaian,cretaceous, pleistocene

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

This refers to weather and atmospheric conditions measured over a long period of time.