[Q]: What is the missing first step of the following process: - The air travels into the windpipe - The windpipe divides the air to the two lungs via the bronchial tubes - The lungs oxygenate the blood in the body - Carbon dioxide is filtered out by every cell in the body - The carbon dioxide is carried back to the lungs via the bloodstream - The carbon dioxide is exhaled.
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[A]: Air is taken into the body via the nose or mouth

[Q]: What is the missing first step of the following process: - Sulfur in the coal combines with oxygen to form sulfur oxides - The sulfur oxides are released into the atmosphere - The sulfides combine with oxygen in the atmosphere to form sulfur trioxide - The sulfur trioxide reacts with water in the atmosphere to form sulfuric acid, a very strong acid - The sulfuric acid makes the rain acidic -
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[A]: Coal is burned

[Q]: What is the missing first step of the following process: - Eventually it burns all its hydrogen - Becomes a red giant - Once the red giant burns itself out - The core of the star collapses - The gasses will start to disperse - Only the core is left - A white dwarf has been formed.
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[A]: A star burns in space

[Q]: What is the missing first step of the following process: - The oxygen passes through the bronchial tubes to the lungs - The oxygen is moved into the bloodstream - Circulates through the body - The cells in the body exchange the oxygen with carbon dioxide - The bloodstream carries the carbon dioxide back to the lungs - The lungs expel the carbon dioxide through the nose and mouth.
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[A]:
A person breathes in oxygen