Use the Graph and Information Provided in the Paragraph Below

Multiple Choice

Use the graph and information provided in the paragraph below to answer the following questions.
Flycatcher birds that migrate from Africa to Europe feed their nestlings a diet that is almost exclusively moth caterpillars. The graph below shows the mean dates of arrival, bird hatching, and peak caterpillar season for the years 1980 and 2000.

-The shift in the peak of caterpillar season is most likely due to

A) pesticide use.
B) earlier migration returns of flycatchers.
C) an innate change in the biological clock of the caterpillars.
D) global warming.
E) acid precipitation in Europe.