Refer to the Figure Showing a Countercurrent Exchanger from a Fish

Multiple Choice

Refer to the figure showing a countercurrent exchanger from a fish gill. The values in the figure represent percent saturation of O₂.Based on the information provided, which statement is true?

A) Fluid flowing through A represents water and B represents blood.
B) Fluid flowing through B represents water and A represents blood.
C) The change in O₂ levels is accomplished by transfer of hemoglobin from tube A to tube B.
D) The change in O₂ levels is accomplished by transfer of hemoglobin from tube B to tube A.
E) The direction of flow in both tubes is from left to right.