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.