input question: What is the missing first step of the following process: - Is exposed to air - A chemical reaction occurs - The iron starts to oxidize - The iron starts to rust.???
output answer: Iron is exposed to oxygen

input question: What is the missing first step of the following process: - Attach a rocket - Add rocket fuel - Launch rocket - Satellite goes into orbit.???
output answer: Build a satellite

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

input question: What is the missing first step of the following process: - The sediments become glued together - The glued together parts become hard like cement - The sediment becomes a big rock - The rocks erode slowly - The rocks come apart - The rocks become smaller rocks - The rocks continue to erode into smaller rocks - The process starts again.???
output answer:
Minerals fill spaces between bits of sediment