How many resurgent domes occupy the Yellowstone caldera?

The Yellowstone caldera contains two primary resurgent domes: the Mallard Lake Dome and the Sour Creek Dome. These domes are formed by the uplift of the Earth's crust due to magma movements beneath the surface. The caldera itself, created by a massive volcanic eruption, is a significant geological feature that reflects the ongoing volcanic activity in the region.