Explosive eruptions of pyroclastic debris and gases are associated with which type of volcanoes?

Which of there factors contributed most to us westward expansion in the second half of the nineteenth century?

What does the word submerged mean in the following sentence? after it rained for three days in a row, the streets were completely submerged.

Can someone me choose a broad topic and area of focus i am really doing this as a tally to see which one most people pick ok water pollution global warming endangered species atmosphere for the !