A student builds a model of the heart and brain, shown in the diagram. Two trucks, 1 and 2, travel between the organs. The student will label the trucks with what they are carrying.
Which set of labels BEST completes the model?
A) Truck 1 carries oxygen and Truck 2 carries carbon dioxide.
B) Truck 1 carries carbon dioxide and Truck 2 carries oxygen.
Eliminate
C) Truck 1 carries red blood cells and Truck 2 carries white blood cells.
D) Truck 1 carries white blood cells and Truck 2 carries red blood cells.
