[Q]: What is the missing first step of the following process: - The pressure causes plates to move - Magma explodes to the surface - The lava from the eruption cools to form new crust - After several eruptions, the rock builds up and a volcano forms -
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[A]: Magma rises through cracks in the Earth's crust

input: Please answer the following: What is the missing first step of the following process: - The items are sorted - Trash is removed from everything else - Goes to a landfill - The items go into a baler machine for each kind of material - They come out as bales - The bales are shipped to manufacturers to use to make products.
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output: Items are collected

Please answer this: 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

Problem: What is the missing first step of the following process: - Your thermostat sends a signal to your heating system to provide heat for your home - When your oil burner is engaged, heating oil travels from the tank to the burner by way of a pump - Here the oil becomes a fine mist mixed with air - The fuel/air mixture is then injected into the burner where it is ignited in the combustion chamber - The warm air is disbursed through vents, hot water through baseboards, or by steam radiators -

A: Your thermostat senses that the room temperature has fallen below your thermostat setting

Problem: Given the question: What is the missing first step of the following process: - Rain picks up carbon dioxide as it falls to earth - The rain falls on the soil over the limestone - The carbon dioxide in the rain washes through the soil - The carbon dioxide turns into acid - The acid in the rain gets to the limestone below the soil - The acid dissolves the limestone - Acid continues to erode the limestone with more rain over time - The eroded limestone sometimes forms caves.
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The answer is:
Limestone is located under the soil

Problem: 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 -

A:
Water comes into contact with something made of iron