Which two processes commonly generate magma?
a. compression melting and wet melting (the addition of volatiles)
b. decompression melting and wet melting (the addition of volatiles)
c. compression melting and dry melting
d. decompression melting and dry melting

b. decompression melting and wet melting (the addition of volatiles)

Explanation: Magma is a hot liquid made of melted minerals, these minerals can form crystals when they are cold.

There are two main mechanisms through which rocks melt at the mantle plumes are; decompression melting and flux melting.

1) Decompression melting takes place within Earth when a body of rock is held at approximately the same temperature but the pressure is reduced. In other words, If a rock that is hot enough to be close to its melting point is moved toward the surface, the pressure is reduced, and the rock can pass to the liquid side of its melting curve.

2) flux melting: this occurs when water and other volatile components ( e.g carbon dioxide) are introduced to hot solid rock, depressing the solidus enough to cause melting. In other words, if a rock is close to its melting point and some water ( which acts as a flux that promotes melting) is added to the rock, the melting temperature is reduced and partial melting starts.