The Pacific Ring of ____________ is an area of violent geological ...

[Tazate]

The Pacific Ring of ____________ is an area of violent geological activity surrounding much of the Pacific Ocean. It
  is an area early seismologists studied to understand patterns of earthquakes. Fill in the blank(s) with the appropriate word(s).

Question 2

Charles Darwin and Alfred Russell Wallace proposed the mechanism of ____________ selection in the 1850's to
  describe how new kinds of living things might come about. Fill in the blank(s) with the appropriate word(s).

[orangecrush]

Answer to Question 1

Fire

Answer to Question 2

natural

[Tazate]

TYSM

[Kedrick2014]

Thanks for the timely response, appreciate it