by 1800 the world population was 1 billion people civilizations existed for thousands of years prior to 1800 based on your knowledge of world history why do you supposed to take the world population to reach a billion by 1800

I think its 100,000 years it would be 1 billion at 1800s

just took the test the answer is b.

since there isn't any suggested answers i will give you the reason and hopefully you can figure it

south africa, or rather all of africa, has not been in the location in which it is nowadays throughout the geological past. after the super-continent pangaea started to break apart, gondwanaland, in which was africa, moved further south, and parts of it came to be very close to the south pole. because the climate in this part of the world is very cold due to the very dispersed sun rays in there, what is now south africa, started to freeze, and the conditions were right for the formation of glaciers. the glaciers existed up until the period when gondwanaland started to break apart and what is now africa started to move towards north, sp it warmed up and the glaciers melted.