Water from nearby rivers or lakes is usually use to cool down the reactors in nuclear power plants the release of this heated water back into the river or lake would most likely result in

Water from nearby rivers or lakes is usually use to cool down the reactors in nuclear power plants the release of this heated water back into the river or lake would most likely result in a change in the variety of life in the waters. It would change since life in that area should adapt to the change in the temperature due to the nuclear reactor.

When you are making a guess you are forming a hypothesis

Average growth population growth