1) The word "book" contains two vowels: O and O.

2) The global response to climate change includes the Paris Agreement, an international treaty aiming to limit global warming and strengthen countries' efforts to address climate change through mitigation and adaptation strategies.

3) Political campaigns involve strategic activities, such as advertising, public appearances, and grassroots organizing, aimed at promoting a candidate or political party and gaining support during elections.

4) The French Revolution, which began in 1789, marked a major turning point in European history, leading to the overthrow of the monarchy and the rise of republicanism.