Which of earth's layers is formed by volcanic activity?

a. mantle

b. inner core

c. outer core

d. crust

D. Crust

An volcanic eruption is a natural expulsion of gases, hot lava, dust and rocks from the undersurface of earth. The released lava gets cool and solidifies into a layers of crust. A volcanic eruption is the earth's way of renewing itself. A volcano can be active, dormant or in extinct state. An active volcano involves an erupting lava, gas and shows seismic activity. A dormant volcano is the one that has not erupted for quite a long time but can erupt in future. A extinct volcano is the one that has been dormant or static for long time and has not shown any sign of activity.

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