It would be "party leadership" that is the most common party system in the world today, although it should be noted that there are still many unitary and dictatorship-based governments.
The factors that made it difficult for Eastern Europe to improve its water quality were outdated sewer systems, raw water quality, worn-out water utilities and unskilled employees. So we can say that four options given in the question fits the bill perfectly. These basic infrastructural reasons were responsible for being a hurdle towards improving the water quality. <span />
Answer:
Before World War I Germany was a prosperous country, with a gold-backed currency, ... The Weimar Republic was politically fragile.
Virginia, north carolina, tennessee, arkansas, south carolina, mississippi, florida, alabama, georgia, louisiana and texas all seceded by april 1861
