Why is the adaptive immune system considered a darwin machine?

"They can evolve at the same rate as pathogens. Produces cells at massive variation, the ones that works get to reproduce. And having variation, section, and inheritance to keep up with the pathogens."
-Quizlet

The outlines of the continents flanking the Atlantic Ocean are so similar that their correspondence was apparent as soon as accurate maps became available. The earliest references to this similarity were made in 1596 by Flemish cartographer Abraham Ortelius and later in 1620 by the English philosopher Francis Bacon, in his book Novum Organum, and by French naturalist Georges-Louis Leclerc, count de Buffon, a century later. Toward the end of the 18th century, Alexander von Humboldt, a German naturalist, suggested that the lands bordering the Atlantic Ocean had once been joined.