input: Please answer the following: What is the missing first step of the following process: - Air enters bronchioles - Bronchioles have tiny air sacs called alveoli - Alveoli surrounded by small blood vessels - Oxygen absorbed by small blood vessels - Vessels deliver oxygen to every cell in the body - Blood brings carbon dioxide back to lungs - Carbon dioxide released when you exhale.
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output: Air enters the lungs through bronchial tubes

input: Please answer the following: What is the missing first step of the following process: - The earth changes energy from the sun into heat - Heat rises from the ground - Greenhouse gas molecules in the atmosphere prevent the heat from going into space - The temperature of the earth increases - The temperature continues to rise and melts the polar ice caps - The temperature rises even faster.
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output: Greenhouse gases are released into the air by human activities

input: Please answer the following: What is the missing first step of the following process: - Bloodstream - Cells in the body are attacked - Cells are killed - Different kinds of sickness are formed.
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output: Bacteria enters the body

input: Please answer the following: What is the missing first step of the following process: - Your stomach digests the food - Sugars from food enter your bloodstream - Insulin helps turn sugars into energy - Insulin helps your body store the energy in fat, muscle and liver cells -
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output:
You eat food