Answer: How explosively or quietly a volcano erupts is not affected by the:
C) concentration of dissolved gases in the magma.
Explanation: Therefore, when a volcano is explosive or less explosive, is as a result of the composition of magmas in different areas or location.
The basic theory of plate tectonics is that along seafloor spreading zones, the continents are separating from one another. As they spread apart, magma comes to the surface and becomes new continental crust. As the tectonic plates move away from spreading zones, they collide with one another.
Western European nations maintained democratic political systems.