Consider the nearby figure, which shows how Virginia pepperweed responds to herbivores. Which of the following conclusions can we make solely using the data shown?
I. Plants increased glucosinolate production when aphids were present.
II. Plants with more glucosinolate and trichomes had fewer aphids.
III. Producing glucosinolate and trichomes reduced plant fitness when aphids were absent.

Question

Quizplus · Accepted Answer

We can conclude from the figure that: 
I. Plants increased glucosinolate production when aphids were present. (supported by the increase in glucosinolate content when aphids were present)
II. Plants with more glucosinolate and trichomes had fewer aphids. (supported by the negative correlation between aphids and glucosinolate/trichome content)
We cannot conclude from the data whether producing glucosinolate and trichomes reduced plant fitness when aphids were absent, therefore III is not supported.

Consider the Nearby Figure, Which Shows How Virginia Pepperweed Responds