List what new features appeared in the development of the leading countries of the world in the 19th century.

In the 19th century, an industrial revolution has already taken place in the leading countries of the world, which made it possible to make industry the main economy. The composition of society has changed: the peasants have ceased to represent the bulk of the population. Most of society was the proletariat, which was formed from peasants who came to the cities to work in enterprises. A class of the bourgeoisie was also formed, which owned capital and enterprises.