Match the missing words in the following phrase. Darwin's principle of 'descent with modification' describes the balance between fitness and [A]. Natural [B] are acted on by [C], favoring individuals with the best [D] for that particular environment.
The Meselson-Stahl experiment used DNA containing 14N and 15N to show that DNA replication is semi-conservative. If replication had been conservative (i.e., one double helix formed of 'old' DNA, and one completely new double helix), what would have been the expected outcome of the experiment after one round of replication?
A) Half the DNA would have 14N density and half would have 15N density. B) All the DNA would have14N density C) All the DNA would have15N density D) All the DNA would have density intermediate between14N and 15N