input question: What is the missing first step of the following process: - Blood is carried to the kidneys through the renal arteries - The kidneys contain filters inside - The filters capture the waste products - The waste is combined with water to make urine - The urine leaves the kidney and is collected in the bladder - The cleaned blood is returned to the body.???
output answer: Waste products are deposited in the blood

What is the missing first step of the following process: - Cells with chlorophyll in them capture the light energy - Plants absorb carbon dioxide through their stoma - Plants absorb water through their roots and other parts of themselves - Plants absorb minerals through their roots - Plants convert these inputs into sugars - Sugars can be used as energy sources - Oxygen and water are also produced - Excess water and oxygen are released through stoma and other parts of the plant.
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Answer: Sunlight shines on plants

Q: What is the missing first step of the following process: - The cracks get very long and big in some places - The earth places pressure against the rocks on both sides of the cracks - The pressure causes the rocks to press against each other very hard - The cracks continue to develop - The earth moves against itself on both sides of the cracks - The pressure and movement around the cracks causes the rocks to crumble in some places - A lot of energy is released - The energy causes seismic waves - The seismic waves move the earth in an earthquake.
A: The earth develops cracks deep beneath the surface

Question: What is the missing first step of the following process: - The light energy is used to convert carbon dioxide - The plant uses nutrients in the soil - The plant uses carbon dioxide in the air to produce glucose - The plant uses the glucose to give itself energy - Oxygen is released as a by product.
Answer: Light energy is absorbed by chlorophyll in a plant

[Q]: What is the missing first step of the following process: - Aluminum flows into streams and lakes - Acid rain dissolves minerals and nutrients in soil - Washes them away so plants can't benefit from them - PH in soil and water gets affected which can kill plants and animals - Acid rain in fog at higher elevations can strip foliage off trees.
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[A]: Acid rain leaches aluminum from clay particles in soil

Problem: Given the question: What is the missing first step of the following process: - The water comes into contact with the rock below - The rock over the years carves through the rock - The space in the rock becomes larger and forms into a cave - As more rather rushes through the cave becomes a cavern.
++++++++++++++++++++++++++++++++
The answer is:
Water from the surface seeps below the soil