1) The Earth's core is hotter than the surface of the Sun.

2) 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.

3) 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.

4) The eye of a cyclone is a region of calm, relatively clear skies and light winds at the center of the storm.