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?
Answer
A
The blood moving toward the hand contains oxygen.
B
The blood moving away from the hand picks up oxygen.
C
Veins carry oxygenated blood and are deep in the skin.
D
Arteries carry deoxygenated blood and are deep in the skin.
Explanation
A tight bandage can stop blood from reaching the hand, so the fingers become cold and blue. With a looser bandage, blood can still flow toward the hand but has difficulty flowing back, causing swelling. Harvey could conclude that blood moving toward the hand carries oxygen; this matches choice A.
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