What asian nation had been carved into "spheres of influence" controlled by european nations by 1900?

China. It was largely caused by the Open Door policy.

Ifound this on google “the existence of agglomeration economies is central to the explanation of how cities increase in size and population, which places the phenomenon on a larger scale. the concentration of economic activity in cities is one reason for their development and growth.” i hope this you for what your looking for.