An extinct volcano

A divergent plate margin volcano

A shield volcano above a mantle plume

A stratovolcano above a subduction zone

A dormant volcano. 

Fayalite, the iron-rich olivine end-member

Biotite, because it is a mafic mineral

Forsterite, the magnesium-rich olivine end-member

Quartz, the mineral at the end of Bowen's Reaction Series

Melting in an impact environment can happen due to a momentary, extreme increase in P-T

Melting within the oceanic crust happens by penetrating water, so a change in 'W'

Mantle melting at oceanic hotspots is related to higher temperatures, or a change in 'T'

Decompressional melting underneath oceanic ridges is triggered through a change in 'P'

Fluxed melting in subduction zones happens through a change in 'X'

it moves from being between the solidus and liquidus to below the solidus

it moves from being between the solidus and liquidus to above the liquidus

it moves from being above the liquidus to being between the solidus and liquidus

Plagioclase (Pl) and Olivine (Ol). Both can occur in basalt; this must be the right answer. 

Rhyolite and Granite; what else? These high Si solutions will be solid after slow and fast cooling, respectively.  

Gabbro (Gb) and Granite (Gr). The classical pluton pair. 

Anorthite (An) and Albite (Ab), the plagioclase endmembers. Look at that ternary diagram and you know!

Solid solutions? This is crazy! How can a solution be solid ???