A student wants to know why sandhill cranes fly south for the winter. The student uses a map of North America to
make a model of the paths sandhill cranes take as they
migrate. The student draws lines with arrows to show the
routes sandhill cranes are known to take.
Which two issues describe limitations of the student's model?
I A. It does not explain how migrating birds affect trees.
OB. It does not explain why the cranes fly south.
C. It does not show the paths of other migrating bird species.
D. It does not show when the cranes arrive at each location.