How Many Years Did It Take for the World Population

Question

How many years did it take for the world population to reach approximately one billion?
A) 10 million
B) 2.5 million
C) 100 million
D) 300 million
E) 1.5 million

Accepted Answer

The world population reached approximately one billion in 1804, which was about 2.5 million years after the first humans appeared on Earth.