When scientists use the term "ring of fire" to what are they referring?

a. a cyclical process involving fire, lava, and volcanoes
b. a large mountain range in southern california that has several wildfires every year
c. a song by country artist johnny cash
d. the rim of the pacific plate where many earthquakes and volcanoes form

How has the elimination of trade barriers affected the movement of goods among member countries of the european union? a. member countries are able to produce all the goods they need. b. goods can move freely among member countries. c. member countries no longer need to trade with countries outside the eu. d. larger countries are able to import more goods than smaller ones.