Why does blood turn dark red while passing in veins through the body?
Because deoxygenated haemoglobin present in veins looks darker red in colour.
Why does blood turn dark red as it circulates through the body?
Why does bright red colour blood turn dark once circulation begins?
Blood is red in colour. Oxygen-rich blood is bright red as it leaves the heart. When it returns to veins without oxygen, it turns blue. Does it mean that the haemoglobin is turned off in the absence of oxygen?
Why the blood does not dry in our body, while it dries outside our body?
Why does blood flow with high pressure and speed in the arteries and not in the veins?