Favorable variations guarantee successful reproduction.

If a rock originally contained 80 atoms of radioactive parent isotope X; after 4 half-lives, how many atoms of the original parent isotope would remain?

  An irregular surface between two parallel beds that represents a past episode of erosion is called:

An event which a lineage rapidly diversifies in response to an opportunity is called:

What process is used to demonstrate that two rock strata are equivalent?

Populations that have similar individuals that can interbreed and produce fertile offspring are called:

A particular order of fossils in Silurian rocks in eastern Ohio is nearly identical to an order of fossils in Silurian rocks in western New York.  Even though they are from two different locations, they are in fact similar in age.  Choose which principle best supports this conclusion:

Range zones ____.

If a radioactive isotope has a half-life of 50 million years, and a rock sample contains 1/8th of that isotope remaining overall, what is the age of the rock from which the sample was taken?

What is the difference between the relative scale and the absolute scale of geologic time?