What is one way political parties shape public policy

Political parties shape public policy by helping the elected officials who belong to the party work together more effectively.  

Explanation:

Political parties around the world almost have the same strategy by which they manage to shape the public policy. They do this by establishing a strong link between the rulers and the people that are to be governed. For this to happen efficiently, they also need to have a good communication with the people. It is important to include the people in this in order to increase the participation of the people in the political spheres, in order to raise awareness among the people. This participation also ensures and guarantees the true essence of democracy.  

by 1880, germany had more rail lines than great britain and russia.

an interest group is an organization whose members share common concerns, and try to influence government policies that impact those concerns. elected officials frequently complain about the influence of "special interests" on american politics.