10 largest countries of the world in decreasing order with the area of each.

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

Fertility and mortality rates are higher in more developed nations.

All of the following are reasons why deserts extremely susceptible to wind erosion except a. they lack major root systems b. they contain thin, dry soil c. they have very few plants and trees d. they are extremely hot and lack water