Answer:
Birth Rate vs Death Rate
Step-by-step explanation:
The world has witnessed several wars, diseases, plagues, natural calamities etc which fluctuates the population growth. Humans became more enduring with the increase in survival rate.
Birth rate has significantly increased due to urbanization, modernization, health facilities etc which led to a population boom all over the world. The death rate is relatively lower than birth rate. From 18th Century or last 300 years, the population growth rate doubled from 0.5% to 1%. At the beginning of 21st Century almost 75 million people are added to world population every year.
However, there are other reasons as well that contributed extensively to the population expansion. Third World countries or any developing nation has great illiteracy, poverty and education which results in the growth of population.
The statistics prove that the current 7 billion people shall reach 9 billion mark in 2050.
Some of the major effects of Population growth: Natural Resource Depletion, Environment Degradation, Wars and Unemployment.
There is no single reason for population growth as each and every event has contributed to its expansion.