Pegmatites,which Occur in Dikes,are Unusual Among Shallow Intrusive Rocks in That

question 21

Multiple Choice

Pegmatites,which occur in dikes,are unusual among shallow intrusive rocks in that they ____________.

• A)possess porphyritic texture
• B)possess exceptionally coarse grains
• C)are mineralogically identical to the extrusive rock basalt
• D)are glassy,cooling so rapidly that crystals do not have time to form

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Definitions:

Tricuspid Valve

A valve in the human heart that lies between the right atrium and the right ventricle, preventing backflow of blood.

Diastole

The stage of the cardiac cycle during which the heart muscle unwinds and the chambers are permitted to be replenished with blood.

Systole

The phase of the heartbeat during which the heart contracts and pumps blood from the chambers into the arteries.

ECG

Electrocardiogram, a test that measures the electrical activity of the heart to show whether or not it is working normally.