Why Do Magmas Rise Toward Earth's Surface

question 45

Multiple Choice

Why do magmas rise toward Earth's surface?

• A)Most magmas are richer in silica than most crustal and upper mantle rocks.
• B)Magmas are more viscous than solid rocks in the crust and upper mantle.
• C)Magmas are mainly liquid and contain dissolved fluids such as water; most are less dense than the adjacent solid rock.
• D)all of the above

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Definitions:

Variable Overhead Efficiency Variance

The difference between actual variable overhead based on the hours worked and the standard variable overhead for the same activity level.

July

The month that is positioned seventh in the Gregorian calendar year.

Raw Materials Quantity Variance

The difference between the actual quantity of raw materials used in production and the standard quantity expected to be used, multiplied by the standard cost per unit of raw material.

Raw Materials Price Variance

The difference between the actual cost of raw materials purchased and the standard or expected cost, reflecting variances in purchase prices.