Distinguish between relative and radiometric dating
Ernst Mayr and others have noted that they are logically independent.
But this leaves open how the two ideas are evidentially related.
While at Randy's favorite Hollywood nightclub, Julie and Randy rapidly grow closer as Stacey continually rebuffs Fred's advances.
Julie's friends, dismayed by her relationship with Randy, pressure her to get back together with Tommy.
In this passage, Darwin is saying that to determine whether a trait shared by two species is strong evidence that they have a common ancestor, one must be able to judge whether there was selection for the trait in the lineages leading to each.
Scientists testing a rock sample discover that the sample contains three times as many daughter atoms as parent isotopes.