The Scientist Finds That the Heavy Metal Concentration in the Insect-Eating

The scientist finds that the heavy metal concentration in the insect-eating birds of a fragment does not depend on the relative amount of edge habitat of that fragment.Which of the following describes how experimental error may have influenced the results?

A) The density of birds is higher in edge habitat compared to the density in interior habitat.
B) The forest fragments studied were too small,and there was no true interior habitat.
C) The insects eaten by both edge and interior birds do not differ in heavy metal concentration.
D) Heavy metals deposited from atmospheric pollution are equal across the landscape.