silica
caldera
viscous
denser
subduction
divergence
hot spots
earthquakes
Explosions from composite volcanoes occur as a result of gas buildup within them. Shield volcanoes also may erupt explosively if water accumulates inside their vents.
Free-enterprise economy
A, B, and C will hurt an underdeveloped nation. D would help the nation strive into becoming an first would country. The question is asking what will not hurt an underdeveloped nation.