Which mobile game was the first to gross over $1 billion in revenue?

Which game introduced the 'battle royale' genre to the mainstream mobile gaming market?

What company developed the popular mobile game 'Genshin Impact'?

Which of these mobile games features a gacha mechanic most prominently?

What is the term used for in-app purchases that give players a significant advantage in mobile games, often criticized as 'pay-to-win'?