Multiple Choice
Lava flows are typically finer grained than intrusive igneous rocks.Why?
A) Intrusive magma is cooler because it is well insulated by the surrounding rock.
B) Intrusive magma flows onto the Earth's surface and cools very slowly, allowing many small mineral grains to grow.
C) The extrusive magma cools quickly so the mineral grains do not have time to grow.
D) The extrusive magma, because it is deep below the surface, cools very slowly producing very small mineral grains.
Correct Answer:

Verified
Correct Answer:
Verified
Q176: The mechanism of selectively removing the minerals
Q177: Most lavas crystallize to form igneous rocks
Q178: What name would you assign to a
Q179: Mafic rocks like basalt and gabbro _.<br>A)are
Q180: Magmas are formed by partial melting in
Q182: Vesicles are _.<br>A)cavities or bubble-shaped holes formed
Q183: Glassy rocks can form either from extremely
Q184: Olivine is an important mineral in peridotites
Q185: What are vesicles?<br>A)open voids in an igneous
Q186: Which of the following is the major