A fossil that can be used as a marker in time is called a

Which type of map is shown in the image

What did the pattern of earthquakes in the wadati-benioff seafloor zones show scientists? a.) earthquakes occur where the ocean floor reaches its highest temperatures. b.) many earthquakes take place 700 kilometers below the seafloor. c.) slabs of ocean floor return to the mantle in subduction zones. d.) ocean - trenches cause earthquakes.

Given: circle a externally tangent to circle b. how many possible common tangents to circles a and b can exist? 2 3 4