Please answer this: What is the missing first step of the following process: - The plants and floor absorb the the sunlight - The absorbed sunlight is converted to heat - The heat cannot escape the glass - The heat is trapped in the greenhouse - The hot air rises - The colder air at the top is pushed to the bottom - The colder air is then warmed by the floor and the plants.
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Answer: Sunlight passes through the glass into the greenhouse

Please answer this: What is the missing first step of the following process: - A muscle fiber gets a signal from its nerve - Proteins and chemicals release energy to either contract the muscle or relax it - When the muscles contracts the bones connected to he muscle are pulled closer together - When the muscle relaxes the bones move farther apart.
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Answer: Muscles work by expanding and contracting

Please answer this: What is the missing first step of the following process: - The coal is broken down to a smaller material - The coal particles mix with hot air and move in to a boiler - Water in the boiler is pumped and produces steam with the coal - Steam powers turbine blades, which magnetically charge wire coals - The water returns back in to its chamber and the process is repeated -
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Answer:
A type of coal must be chosen before the heating can start