Question

the worlds population took ______ to reach the second billion mark.
a 200 years
b 100 years
c 120 years
d 300 years

Explanation:

The world's population reached the first billion around 1804. It reached the second billion in 1927. The time difference between 1927 and 1804 is 123 years, which is approximately 120 years.

Answer:

C. 120 years