1) The word "computer" contains three vowels: O, U, and E.

2) The concept of proportional representation, used in some electoral systems, aims to ensure that political parties' representation in government aligns more closely with the proportion of votes they receive from the electorate.

3) The concept of federalism involves the division of powers between a central government and regional or local governments, allowing for shared governance and autonomy for different levels of administration.

4) The croissant, a flaky and buttery pastry, is an iconic French delicacy. It is made by layering dough with butter, rolling and folding it multiple times to create a laminated structure. The croissant can be enjoyed plain or filled with various ingredients, such as chocolate, almond paste, or ham and cheese. It has become popular worldwide and is a staple in breakfast menus and bakeries, symbolizing French culinary expertise and savoir-faire.