What geographic feature isolate japan?

What is the primary justification of the hypothesis that the early earth environment was void of oxygen? ( 2 points) data showing the concentrations of gases extracted from rocks fossil evidence regarding the origin of eukaryotes generally accepted atmospheric conditions molecular evidence based on evolutionary traits.

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

What are the answers for the following questions?