THE EARTH
PHYSICAL GEOGRAPHY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Extrusive igneous rocks have
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Few grains
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No grains
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Grains of big size
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Grains which are not visible
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Explanation:
Detailed explanation-1: -Extrusive igneous rocks have a fine-grained or aphanitic texture, in which the grains are too small to see with the unaided eye. The fine-grained texture indicates the quickly cooling lava did not have time to grow large crystals. These tiny crystals can be viewed under a petrographic microscope [1].
Detailed explanation-2: -Because extrusive rocks make contact with the atmosphere they cool quickly, so the minerals do not have time to form large crystals. The individual crystals in an aphanitic igneous rock are not distinguishable to the naked eye.
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