Q: What is the missing first step of the following process: - Through erosion, the stream cuts into the soil and bedrock - Through continuous erosion, a deep gash is cut through - After many years the river may dry up - A dry ravine is left -
A: A stream or river must occur

Q: What is the missing first step of the following process: - The owl flys out into the night - The owl looks down at the ground - The owls keen eyesight allows him to see in the dark - The owls sensitive hearing allows him to locate hidden prey - The owl swoops down - The owl catches a mouse in his talons.
A: An owl leaves his nest

Q: What is the missing first step of the following process: - The heated water evaporates - The salt is left behind - The evaporated water condenses on a cold surface - The evaporated water is collected - The process is repeated - More salt is removed from the water.
A: Water is heated

Q: What is the missing first step of the following process: - The pollution negatively affects the water quality - The pollution negatively affects the health of plants and animals - The plants and animals have shorter, less healthy lives - The plants and animals do not reproduce very well - The number of plants and animals decreases over time - The quality of water gets worse and worse as there are no plants or animals to clean it - Eventually there is nothing living in the water and it is unusable -
A:
Pollution enters natural water sources such as rivers and lakes