Why do magmas rise toward Earth's surface?

Question

Question: Why do magmas rise toward Earth's surface?

Options:

1.  Magmas are more viscous than solid rocks in the crust and upper mantle.
2.  Most magmas are richer in silica than most crustal and upper mantle rocks.
3.  Magmas are mainly liquid and contain dissolved fluids such as water; most are less dense than the adjacent solid rock.
4.  All of the above

Answer 1

3. Magmas are mainly liquid and contain dissolved fluids such as water; most are less dense than the adjacent solid rock.

Magmas rise toward Earth's surface because they are mainly liquid and contain dissolved fluids such as water; most are less dense than the adjacent solid rock.

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