Rebecca Olien

"Describes how cities treat freshwater so that it is safe to drink"--

"A description of the Earth's water sources, salt water, and freshwater"--

Describes the physical characteristics, behavior, food, predators, and habitat of squirrels, as well as their relationship with people.

"Describes the sources of freshwater on the earth and ways people can conserve water"--

"Discusses the history, function, and workings of rescue helicopters"--Provided by publisher.

"Learn about the job of the nervous system, problems that may come up, and how to keep the system healthy"--Provided by publisher.