19. According to the passage, how many teams of researchers had studied the Humboldt penguins on Damas, Choros, and Chanaral before Ellensburg’s team did so?
Your Answer is
Correct Answer is A
Explanation
The stem requirement: "Before Ellenberg, how many teams have studied Humboldt's penguins?" line 63, "Ellenberg's team was the first to study the number of these penguins." So the corresponding item is A p>