What is the ethnicity of the maori?

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

Can someone me with this plz? ! i'm putting 20 points on it!

1. crust 1 the metallic layer at the earth's center 2. inner core 3 the firm layer between the crust and the asthenosphere 3. lower mantle 2 the layer surrounding the inner core 4. asthenosphere 4 the semi-solid layer between the top layer and the upper mantle 5. upper mantle 5 the layer between the asthenosphere and lower mantle 6. top layer 6 the earth's outermost layer 7. outer core 7 the hottest part of the mantle