HURRY PLZ 40 POINTS
Which statement best explains why blood is “waste-rich” when it returns to the heart?
The blood has a high concentration of oxygen and a low concentration of carbon dioxide.
The blood has a high concentration of oxygen and a low concentration of hemoglobin.
The blood has a high concentration of carbon dioxide and a low concentration of oxygen.
The blood had a high concentration of hemoglobin and a low concentration of oxygen