Well the first one, and the fourth one.
The main way in which World War I hurt business in Europe even after the war was that Europe was economically devastated and had focussed all their production on war materials, meaning there was a lack of goods and services after the war.
In general, the Industrial Revolution, which originated in Great Britain, opened up lots of new opportunities for employment for people, which created a solid middle class.
Answer:
There are currently around 7.6billon people living right now