19. Compared to the author of Passage A, the author of Passage B provides more information about the:

  • A. reduction in the number of apple varieties in North America over the past four centuries.

  • B. methods Vavilov used to prove to other scientists that the apples growing in the Tian Shan are the ancestors of the modern apple.

  • C. number of apple varieties that are thriving in Kazakhstan today. 

  • D. techniques used by researchers to determine the regions with the greatest genetic diversity in plants