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?

Answer and Explanation

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