What role has industrialization played in population growth

I believe the answer is: improved healthcare, technology, sanitation, carrying capacity---which leads to people living longer and having more babies

Here are several reasons why fertility rate in an area could go down:

- Increased death rate among young people

- Unsanitary environment which could resulted in various type of diseases

- Problems during child bearing

- not having enough money to sustain family's health.

All of the things that mentioned above address all of these low fertility rates issues