How did cities address the problems caused by urban living?

"Governments began to offer services such as mass transit and sanitation" is the answer you are looking for that the cities addressed the problems caused by urban living.

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.