I might go with d it seems right to me hope this helps.
<span> under extreme heat or pressure
crystallize from magma
precipitate from a solution reaction of hot mixture with water and a dissolved substance</span>
Earthquakes make the surface all cracky and hard where it’s hard to dig up and the soil is like hard to step on because one false move and you could fall down
Dont know the first part but melanin quantities change the dkin color
