Why is the texture of the igneous rock obsidian glassy?

A) Obsidian commonly forms at the surface of lava flows.
B) Obsidian always forms beneath the earth's surface.
C) Obsidian is aphanitic.
D) Obsidian is phaneric.


Answer: B

Environmental & Atmospheric Sciences

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A spinning cloud of interstellar gas tends to

A. condense. B. disperse. C. turn into a sphere. D. flatten.

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What were some key consequences from the break-up of Pangaea?

a. Rise of sea level, increase of shallow marine habitat, species diversification, climate change - mild and warm b. Rise of sea level, decrease of shallow marine habitat, species diversification, climate change - mild and warm c. Lowering of sea level, decrease of shallow marine habitat, increased species extinction, climate change - mild and warm d. Lowering of sea level, increase of shallow marine habitat, species diversification, climate change - increased glaciation

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Use your knowledge of plate boundaries to answer whether a volcano is likely or unlikely to form at the location of the red triangle.



A) Likely
B) Unlikely

Environmental & Atmospheric Sciences

Most of Earth's weather occurs in this "sphere," the ____________________

Fill in the blank(s) with correct word

Environmental & Atmospheric Sciences