secularisation’ to an understanding of European history since 1500

answer each question in one page. there are 3 questions:
1) How useful do you find the concept of secularisation’ to an understanding of European history since 1500?
2) What, if any, was the connection between the French Revolution and the rise of nationalism’ in Europe in the 19th century?
3) What was the impact of industrialization on European society in the period c.1870-1914?