Progressive reformers tried to remedy problems created by a0 and urbanization through political action.

Industrialization

Explanation:

Progressive reformers tried to remedy problems created by industrialization and urbanization through political action. These problems usually involved poverty and inequality. As cities became more industrialized, more people moved to these areas looking for work in factories and new businesses. New immigrants also came from abroad for the same reasons. This led to the creation of poor, urban communities in these new cities. The progressive reformers wanted to deal with these by using political means.

The answer would be: Industrialisation