Why is the blood that flows from the lungs toward the heart a brighter red than the blood that flows the other direction? The presence of pigments found in the lungs makes it bright red. The presence of oxygen–bound hemoglobin makes it bright red. The presence of carbon–dioxide–bound hemoglobin makes it bright red.

Question

Why is the blood that flows from the lungs toward the heart a brighter red than the blood that flows the other direction?  The presence of pigments found in the lungs makes it bright red.  The presence of oxygen–bound hemoglobin makes it bright red.  The presence of carbon–dioxide–bound hemoglobin makes it bright red.

anonymous · Answer

The presence of carbon–dioxide–bound hemoglobin makes it bright red.

anonymous · Answer

The presence of oxygen

anonymous · Answer

how do i ask more

anonymous · Answer

The body wants to get rid of carbon dioxide for that it can't be @naresa response. That's why the answer is the presence of oxygen-bound hemoglobin that makes it bright and red.