Is human blood yellow?

No, human blood is not yellow. Human blood is typically red due to the presence of hemoglobin, a protein that carries oxygen and gives blood its red color when it binds to oxygen molecules. The color of blood can vary depending on its oxygenation level. Oxygenated blood, which is rich in oxygen, appears bright red, while deoxygenated blood, which has lower oxygen levels, appears darker red.

The misconception that blood is yellow might arise from the fact that veins, which carry deoxygenated blood back to the heart, often appear bluish or greenish through the skin. This is due to the way light interacts with the skin and the underlying blood vessels. The skin's color and thickness can affect the way we perceive the color of blood vessels, but the blood itself is not naturally yellow.