input question: What is the missing first step of the following process: - Then while gathering of their food, they make wax, which is the building block of their bee hive - Bees make food called honey - They use a sticky, glue-like substance called propolis as a binding to hold their hives together - Bees produce all of the building blocks to build their hive in their own body -???
output answer: Bees go out during the day and gather food

What is the missing first step of the following process: - The sound travels in waves, as sound does - The sound "bounces" off of a nearby object - The sound wave returns to the bat - The bat hears the echoed sound - Folds in the bat's ear and adaptations in the bat's brain enable it to determine the size, shape, and position of the other object via the properties of the returned sound waves - Other animals use echolocation in generally similar ways -
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Answer: Bats and other animals produce a high-pitched tone

Q: What is the missing first step of the following process: - Enters the lungs - The oxygen fills the sacs in your lungs - Carbon dioxide is removed from the lungs and exhaled - The oxygen is pass throughout your body.
A: Air is taken through the mouth

Question: What is the missing first step of the following process: - Under the right conditions it can develop further and start to spin around a low-pressure center - If it develops it's classified as a 'tropical cyclone' or 'tropical depression' - If the system strengthens and wind speeds rise past 39 mph, the system is dubbed a 'tropical storm' - If the pressure in the center drops even further and the winds really pick up and forms a clearly defined 'eye' it's a hurricane -
Answer: A hurricane usually starts as an organized thunderstorm activity that stretches at least 100 miles across and maintains its identity for more than 24 hours

[Q]: What is the missing first step of the following process: - Is trapped - Plant also takes in water and carbon dioxide from the environment - The plant forms glucose - The plant releases oxygen into the atmosphere.
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[A]: Sunlight strikes the chlorophyll molecules in the plant

Problem: Given the question: What is the missing first step of the following process: - After a rain, water seeps into cracks and pores of soil and rock - The water percolates beneath the land surface - Some of the water reaches a zone where all the cracks and pores in the rock are already filled with water - Rainwater absorbs some carbon dioxide as it passes through the atmosphere and even more as it drains through soil and decaying vegetation - The water combines chemically with the carbon dioxide - A weak carbonic acid solution is formed - This acid slowly dissolves calcite, forms solution cavities, and excavates passageways -
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The answer is:
Solution caves are formed in limestone and similar rocks by the action of water