A: Scientists
b:
1)Yes, it does.
2)Recently people have learnt that they walk over one of the largest active volcanoes in the world.
3)The last super eruption at Yellowstone was 640000 years ago.
4)It was such an important event because ash covered most parts of North America, and the Earth's climate changed.
5)It isn't possible to see the hole from the ground because the eruption made such a huge that we can see it from the air.
6)Yes, there are.
7) Recently, the number of earthquakes has increased and in some parts of the park the level of the ground has risen.
8)Yes, they do.