Question

Mantle plumes are areas of hot, upwelling mantle and hot spots develops above these plumes as noted in the map above. Magma generated by the hot spot rises through the rigid plates of the lithosphere and produces active volcanoes at the Earth's surface. As oceanic volcanoes move away from the hot spot, they cool and subside, producing islands, atolls, and seamounts. As the magma cools in the water it forms ___________________ rocks.
A)
metamorphic


B)
clastic igneous


C)
extrusive igneous


D)
intrusive igneous

Answer 1

The answer is C) extrusive igneous. This rock starts as magma, so you know it must be a type of igneous rock. The question tells you that the rock forms when it is cooled by the water, so you know it is formed outside of the Earth's interior, therefore making it extrusive igneous rock.