Looking at the data in the accompanying figure from the hare/lynx experiment, what conclusion can you draw?
I. Food is a factor in controlling hare population size.
II. Excluding lynx is a factor in controlling hare population size.
III. The effect of excluding predators and adding food in the same experiment is greater than the sum of excluding lynx alone plus adding food alone.
A) only I
B) only II
C) only III
D) only II and III
E) I, II, and III

Question

Looking at the data in the accompanying figure from the hare/lynx experiment, what conclusion can you draw?
I. Food is a factor in controlling hare population size.
II. Excluding lynx is a factor in controlling hare population size.
III. The effect of excluding predators and adding food in the same experiment is greater than the sum of excluding lynx alone plus adding food alone.
A) only I 
B) only II 
C) only III 
D) only II and III 
E) I, II, and III

Quizplus · Accepted Answer

The data in the figure show that hare population size is affected by both food availability and lynx predation. The population size drops significantly when lynx are present, indicating that predation is an important factor. However, the population size also drops when food availability decreases, indicating that food is also an important factor. Therefore, both I and II are supported. As for III, it is difficult to determine from the graph alone whether the effect of excluding predators and adding food is greater than the sum of their individual effects.

Looking at the Data in the Accompanying Figure from the Hare/lynx