Explain how scientists use fossils to determine the history of earth.

How does the parallax of a nearby object compare to that of an object farther away?

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

The first atomic explosion was detonated in the desert north of alamogordo, new mexico, on july 16, 1945. what percentage of the strontium-90 ( yr) originally produced by that explosion still remains as of july 16, 2016?