Please answer neatly in steps.

Why don't all places on earth receive the same amount of direct sunlight at the same place?

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

The covers all of earth like a thin shell,but it is not a solid sheet of material.it is broken up into several large sections and many smaller ones. fill in the blank.