1. humans began using stone tools
Industrial Revolution
2. birth rates declined, and the average life expectancy increased
1999
3. the world population totaled six billion people
Paleolithic Era
4. the annual population growth rate reached its peak
late 1960s
Answers
Answer 1
Answer:
I think the answer is either 4 or 2, I'll tell you my confirmed answer in explanation
Explanation:
4. In 1968 was when the population growth rate met it's peak
Answer 2
Birth rates declined the world pop annual pop rate