Why does the infant mortality rate differ from different nations?

Answer 1

That birth rates vary from country to country, is a relatively new phenomenon. The reason why there are different birth rates is that the countries are in a different state of the so called 'demographic transition'. It usually has 4 stages which a country passes:

Stage 1: High birth and high Death Rate (all countries before industrial revolution)

Stage 2: High birth and falling death rate (some African countries)

Stage 3: falling Birth Rate and low death rate (most of the developing countries)

Stage 4: low birth rate and low death rate (developed countries)

The birth rates fall because there's no need for children as workers anymore. Countries in stage 1 and 2 are rural societies that demand child labor in the fields. The people have also to compensate the high Infant Mortality Rate. In stage 3 lesser and lesser people work in agriculture and children are no longer an economic benefit but a burden for the parents.

There's also much divergence in the birth rate in stage 4 countries. Most of the developed countries will go to the Stage 5 of the transition, with a death rate higher than the birth rate. Only two developed countries will not: USA and Israel. This has cultural reasons.

Answer 2

people have lots of babies because they can go out to work at a young age, and get the family money, and also they must like sexual intercourse