What is the color and function of blood?

Blood is an opaque red liquid that flows in the heart and blood vessels, and its main component is plasma? Blood cells?

Maintain our life activities through round-the-clock blood circulation? But why is our human blood red?

So our blood contains hemoglobin? The function of hemoglobin is to transport oxygen and carbon dioxide and maintain the acid-base balance of blood?

Our blood is rich in oxygen, which is oxygenated hemoglobin, so our blood is bright red and venous blood is dark red?

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