1) International relations encompass the study of relationships between nations, including diplomacy, treaties, and foreign policy. It examines the interactions and dynamics among different countries in the global arena.

2) Serena Williams is an American professional tennis player widely regarded as one of the greatest athletes in the sport. She has won numerous Grand Slam titles and Olympic gold medals and has become an influential figure both on and off the tennis court.

3) Gelato, an Italian frozen dessert, is similar to ice cream but has a denser and creamier texture. It is made with milk, sugar, and various flavorings, such as fruit, chocolate, or nuts. Gelato is churned at a slower speed than ice cream, incorporating less air and resulting in a richer consistency. It is served at a slightly warmer temperature than ice cream, allowing the flavors to be more pronounced. Gelato is a beloved treat, particularly in Italy, where it is enjoyed in countless flavors and gelaterias.

4) The word "forest" contains two vowels: O and E.