[Q]: What is the missing first step of the following process: - The water freezes and thaws - Cracks form in the rocks - Cracks also form when rocks heat up - The rocks slowly break down.
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[A]: Water seeps into rocks

[Q]: What is the missing first step of the following process: - The wind or water deposits tiny rocks - The rocks become known as sediment - The layers of sediment are pressed together by other layers of sediment on top - Minerals from the rocks in the sediment dissolve - Minerals glue the sediment together into a single rock.
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[A]: Wind or water breaks small pieces off of a rock

[Q]: What is the missing first step of the following process: - The sediment rolls down hill towards a river - The heavy items sink to the bottom - The lighter items float on the top and in convection cycles - As the river flows the sediment is moved - The sediment gets dumped through tributaries into lakes and the ocean - The sediment keeps moving around the world in convection currents.
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[A]: Sediment becomes loose from the rest of the soil

[Q]: What is the missing first step of the following process: - Air reaches the lungs - The lungs absorb the oxygen from the air - The oxygen is transported by hemoglobin - Red blood cells are made of hemoglobin - Blood has a lot of red blood cells - The heart moves the blood throughout the body - Blood can bring the oxygen to different cells in the body.
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[A]:
Air travels into the body