Which of these developments wa caused in part by the end of the last ice age and its resulting climate change around 9000 BCE?

About 11,000 - 12,000 years ago, the North American climate began to change. Exactly why and how this happened is still debated, but the change coincides with the catastrophic extinction of the big-game animals at the end of the Ice Age. The continental ice sheets were withdrawing and the melt-water from them filled valleys and basins, while the shorelines of the continents began to change as the then existing continental shelves came to be drowned by rising sea levels.