[Q]: What is the missing first step of the following process: - Fill the tray with water from the faucet - Put the ice cube tray in the freezer - Wait for several hours - The water will freeze and become ice - Remove the ice cube tray from the freezer - Remove the ice cubes from the tray.
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[A]: Take out an ice cube tray

[Q]: What is the missing first step of the following process: - Water is absorbed through roots - Chloroplast cells in leaves contain chlorophyll - Chlorophyll absorbs energy from sunlight - Energy splits water molecules into hydrogen and oxygen - Oxygen gets released into atmosphere - Hydrogen and carbon dioxide used to create glucose - Glucose is food for plants.
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[A]: Carbon dioxide passes through stomata in the leaves

[Q]: What is the missing first step of the following process: - Animals gain weight - The season changes to one with bad (cold, snowy) weather - Animals find a place to hibernate - Animals enter a type of 'sleep' (hibernation) - Body processes slow down - The animal's heart rate and breathing rate slow - The animal loses weight more slowly than usual - The animal is able to survive not eating or drinking without hurting itself -
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[A]: Animals eat a lot during good (warm, clear) weather

[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 -
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[A]:
Dead organic material accumulates on the bottom of oceans, riverbeds or swamps, mixing with mud and sand