In dendrochronology, scientists establish historical climate timelines by analyzing the annual growth rings of trees. In years of optimal precipitation and temperature, trees produce wide growth rings, whereas during severe droughts or extreme cold, growth is stunted, resulting in narrow rings. However, an isolated tree sample cannot provide an absolute chronological record because local environmental anomalies—such as localized insect infestations or physical injury to a single tree—can distort its ring sequence. To overcome this limitation, dendrochronologists rely on a method called cross-dating: they compare overlapping ring patterns across dozens of trees of different ages from the same region. By identifying consistent, synchronous sequences of wide and narrow rings across multiple independent specimens, researchers can filter out individual anomalies and construct a reliable master chronology spanning centuries.
Which of the following scenarios is most analogous to the dendrochronologists' practice of cross-dating as described in the passage?
- AA botanist determines the total lifespan of an ancient fallen tree by counting each individual growth ring from the outer bark directly to the central core.
- An economic historian reconstructs a long-term regional commodity price index by comparing overlapping transaction ledgers from several merchant families across successive eras, cross-referencing entries to eliminate idiosyncratic accounting mistakes and individual vendor discounts.Answer
- CA forestry technician surveys a woodland damaged by an insect outbreak to identify which tree species have the thickest outer bark and highest natural resistance to infestation.
- DA meteorologist relies on real-time atmospheric readings from a single high-altitude weather station to forecast precipitation for the surrounding metropolitan area over the next twenty-four hours.
- EAn archivist concludes that because several centuries-old manuscripts display identical ink fading, all of the documents must have been composed by the same historical author.