William Harvey discovered circulation. First, as he tightened a bandage around an arm, he noticed that the fingers turned blue and cold. Then, he used a less tight bandage and noticed that the hand swelled. With further research,
what conclusion could he reach?
The blood moving toward the hand contains oxygen.
The blood moving away from the hand picks up oxygen.
Veins carry oxygenated blood and are deep in the skin.
Arteries carry deoxygenated blood and are deep in the skin.