Problem: What is the missing first step of the following process: - The water rises up in the air - It starts to cools down - The water starts to condense - It forms into clouds - When there is enough moisture in the clouds it starts to rain.

A: Warm weather causes water to evaporate

Problem: 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.

A: Take out an ice cube tray

Problem: What is the missing first step of the following process: - Waves have energy that pushes the water and sediment - The sediment can help erode land like sandpaper - Water washes the sediment back - Some sediment is left as sand.

A: Waves hit the coast

Problem: 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.

A:
Waste products are deposited in the blood