<span> under extreme heat or pressure
crystallize from magma
precipitate from a solution reaction of hot mixture with water and a dissolved substance</span>
a. Emma creates a pressure difference allowing the fluid to flow.
KCI is not a covalent compound, it is an ionic compound.
A covalent compound is one in which each of the atoms involved contribute a specific number of electrons for sharing in order to from stable compound while an ionic compound is a compound formed when one atom donates electron to the other atom in the compound, in order to attain stability. The compounds given in options A, B and D shared electrons while in KCl, potassium donates an electron to chlorine.