input question: 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.???
output answer: Water gets into cracks in rocks

What is the missing first step of the following process: - The trees die off - The dead material provides nutrients for more trees - The rising trees provide shelter - And more organisms begin to thrive - The ecosystem known as a forest is made.
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Answer: Networks of trees start forming

Q: What is the missing first step of the following process: - Over time, more sediment piles on top - The resulting heat and pressure transforms the organic layer into a dark and waxy substance known as kerogen - Left alone, the kerogen molecules eventually crack - The molecules break up into shorter and lighter molecules composed almost solely of carbon and hydrogen atoms - It will turn into either petroleum or natural gas -
A: Dead organic material accumulates on the bottom of oceans, riverbeds or swamps, mixing with mud and sand

Question: What is the missing first step of the following process: - The isotope is unstable - The isotope emits radiation - The isotope decays - The isotope loses some atomic particles - The isotope turns into a different element - The isotope is finished decaying and emitting radiation.
Answer: An isotope has too many protons

[Q]: What is the missing first step of the following process: - Release them into the air by process of sporulation - Spores are carried by the wind - Land in a hospitable growing environment - The spores germinate into the soil - The mushroom starts growing - The adult mushroom produce spores of its own to repeat the process.
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[A]: Adult mushrooms produce spores

Problem: Given the question: What is the missing first step of the following process: - Air enters bronchial tubes - Air is then split into the bronchioles of each lung - Bronchioles have alveoli which are tiny air sacs - Alveoli is surrounded by many small blood vessels - Oxygen passes through alveoli into blood vessels - Blood leaves the lungs as it travels through the body - Blood carries carbon dioxide back to the lungs - Carbon dioxide released when you exhale.
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The answer is:
You breathe air in