Problem: What is the missing first step of the following process: - The water freezes into ice - The cracks expand - Over time the rocks split - The rocks are now in smaller pieces.

A: Water gets into cracks in rocks

Problem: Given the question: What is the missing first step of the following process: - After a rain, water seeps into cracks and pores of soil and rock - The water percolates beneath the land surface - Some of the water reaches a zone where all the cracks and pores in the rock are already filled with water - Rainwater absorbs some carbon dioxide as it passes through the atmosphere and even more as it drains through soil and decaying vegetation - The water combines chemically with the carbon dioxide - A weak carbonic acid solution is formed - This acid slowly dissolves calcite, forms solution cavities, and excavates passageways -
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The answer is:
Solution caves are formed in limestone and similar rocks by the action of water

input question: What is the missing first step of the following process: - The sound waves hit an object - Echoes are produced - The echo returns to the bat's ears - The bat hears the echo - The bat can figure out where the object is located.???
output answer: The bat sends out sound waves from their mouth or nose

What is the missing first step of the following process: - Food is squeezed down the esophagus when you swallow - Acid and enzyme in the stomach break the food down - Releases nutrients - Food then pumped into small intestine - Fluid and enzymes from liver and pancreas pumped into small intestine - Help break food into smallest molecules - Nutrients pass through wall of small intestine - Nutrients absorbed into blood stream - Unused materials passed into large intestine to become fecal matter.
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Answer: An enzyme in saliva begins to break down carbohydrates

Q: What is the missing first step of the following process: - The heated water evaporates - The salt is left behind - The evaporated water condenses on a cold surface - The evaporated water is collected - The process is repeated - More salt is removed from the water.
A: Water is heated

[Q]: What is the missing first step of the following process: - The top layer are 'doped' with impurities to allow a negative charge - The bottom layer are 'doped' to allow for a positive charge - This produces an electric field that allows electrons to flow from negative to positve - Sunlight enters the cell - Energy from sunlight knocks electrons loose in both fields - This prevents the flow of electrons from negative to positive - Adding an external circuit allows the exchange to continue - Give the cells owner a flow of electricity.
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[A]:
A photovoltaic cell is created with two layers of semiconductor material