input: Please answer the following: What is the missing first step of the following process: - May come from different sources - The gases remain trapped in the atmosphere - Through the suns light the gases hold in heat and energy - Trap them in our atmosphere - The earth may become warmer this way.
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output: Several types of gases form in the atmosphere

input: Please answer the following: 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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output: Limestone is located under the soil

input: Please answer the following: What is the missing first step of the following process: - The gases come to a head and push molten magma to the surface - The magma cools - With enough time the pressure builds up greatly - The resulting volcano may explode.
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output: Gases cause pressure beneath the earth

input: Please answer the following: What is the missing first step of the following process: - Ocean water pulls sand off of beaches - Ocean water breaks rocks off of cliffs - Ocean water carries sand and rocks into the ocean - Sand and rocks go to other land or the bottom of the ocean.
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output:
Ocean waves hit land