Igneous rocks are formed when melted rock deep inside the crust cools and hardens--or erupts at the surface as lava.
(Igneous rocks; are formed; T:when melted rock deep inside the crust cools and hardens--or erupts at the surface as lava)
Igneous rocks
are formed
T:when melted rock deep inside the crust cools and hardens--or erupts at the surface as lava