Many seemingly purposeful animal behaviors turn out, on closer inspection, to be regulated by simple environmental cues. The fall migration of monarch butterflies, for instance, is triggered not by the butterflies' "knowledge" of the coming winter but by the shortening day length, which cues a hormonal cascade preparing them to fly south.
Which choice best describes the function of the second sentence in the text?
- A
It defines the term 'cue'.
- Bcheck_circle
It illustrates the general claim with a specific example involving monarch butterflies.
- C
It refutes the general claim about purposeful behavior.
- D
It introduces a different butterfly species.
Explanation
The monarch case exemplifies the broader claim. B captures this illustrative function.