What is the missing first step of the following process: - The liver uses chemicals and proteins to treat the blood - The blood is cleaned - Energy is produced - The blood leaves the liver cleaned.
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Answer: Blood is sent to the liver

What is the missing first step of the following process: - The oxygen travels into the lungs - The oxygen binds to hemoglobin proteins within erythrocytes (red blood cells) - The erythrocytes are pumped through the body by the heart - All cells receive the oxygen.
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Answer: Oxygen enters the body through the mouth or nose

What is the missing first step of the following process: - The water combines with carbon dioxide in the air to form carbonic acid - As the acid is formed, the iron starts to dissolve - Some of the water breaks down into hydrogen and oxygen - The free oxygen and dissolved iron bond together - They form iron oxide, which is rust -
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Answer:
Water comes into contact with something made of iron