Use the following information to answer the questions below.
The migration path of monarch butterflies brings them from Eastern Canada to Mexico over a long,multi-generational journey.During a series of experiments in a chamber,monarchs were observed to fly in a southwest direction.When their circadian rhythms were altered by -6 and +6 hours,the monarchs flew in a southeast or northwest direction,respectively.
-Which kind of photoreceptor would you expect the butterfly to have?