Passage II
Urushiols are the oils in poison ivy that cause allergic reactions in humans. The higher the U: S ratio－the ratio of unsaturated (U) urushiols to saturated (S) urushiols—the more severe the reaction.
From 1999 to 2004, poison ivy plants (PIPs) were grown in 2 identical outdoor plots under identical conditions except for the atmospheric CO2 concentration.
Figure 1 shows, for each plot, the yearly dry biomass per plant. Figure 2 shows the yearly percent of original PIPs surviving in each plot. Figure 3 shows, for each plot in 2004, the percent of U urushiols per plant, the percent of S urushiols per plant, and the U: S ratio per plant.
Figures adapted from "Biomass and Toxicity Responses of Poison Ivy (Toxicodendron radicans) to Elevated Atmospheric CO2." @2006 by the National Academy of Sciences.
10. According to Figure 1, from 1999 to 2004, how did the dry biomasses per plant for the 2 plots compare? The dry biomasses per plant grown in a CO2 concentration of 370 ppm was:
Your Answer is
Correct Answer is H
Explanation
According to figure 1, when the abscissa is the same, the ordinate of 370 ppm is always smaller than the ordinate of 570 ppm, so the H option is consistent