What do Volcanoes make?

Volcanic irruption is most likely to be violent when a) volcanoes near to the sea b) the neck of the volcano is sealed by a plug c) the lava is viscous d) the lava reaches the surface through a fissure e) the volcano is on the ocean floor

What is the main purpose of the gi bill

One disadvantage that darwin faces today is w. enemy attacks x. natural disasters y. lack of land bridge z. high population density