[Q]: What is the missing first step of the following process: - The female lays eggs - The eggs are incubated by the parents, by sitting on them, for weeks - The bird hatches from an egg - The parents feed them as the continue to grow - Develop flight feathers - The parents teach them to fly - After learning to fly they leave the nest to live on their own - The next year they breed beginning the cycle again -
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[A]: A male and female bird mate

[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

[Q]: What is the missing first step of the following process: - You water the seeds - You wait for the seeds to sprout - You keep the area free of pests and weeds while the plants grow - You thin out the plants as they get bigger to give them space to grow - You remove the vegetables from the plants when they are ripe.
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[A]: You plant vegetable seeds in the ground

[Q]: What is the missing first step of the following process: - Engines produce carbon dioxide - Living things produce waste - Waste decomposes - Decomposition produces methane - Water evaporates - Water vapor joins the atmosphere - Carbon dioxide, water vapor and methane are greenhouse gases -
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[A]:
People breathe and expel carbon dioxide