Edith's Checkerspot Butterflies Are Considered "Indicator Species" Because They

Edith's checkerspot butterflies are considered "indicator species" because they

A) can determine the make up of the community of organisms through predation.
B) are signals for the presence of predators that prey on the butterflies.
C) are important signals of ecological change.
D) are only present during certain seasons.
E) indicate when food supplies are low by changing their behavior.