The two most active volcanic zones are the ____________________ ...

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The two most active volcanic zones are the ___________________ _ belt and the
  ___________________ _ belt. Fill in the blank(s) with the appropriate word(s).

Question 2

At Laki fissure in Iceland, the eruption of the gas ___________________ _ caused about 75 of the
  nation's livestock to die, 25 of the population to die, and crops to fail. Fill in the blank(s) with the appropriate word(s).

[lkanara2]

Answer to Question 1

circum-Pacific; Mediterranean

Answer to Question 2

sulfur dioxide

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TYSM

[Zebsrer]

Thanks for the timely response, appreciate it