
Over 70 percent of Earth is water, but what exactly is in the oceans and lakes that surround us? In this series, readers take an in-depth look at the many creatures that spend their lives completely--or partially--underwater, from fish and mammals that swim in the ocean to sea...

Over 70 percent of Earth is water, but what exactly is in the oceans and lakes that surround us? In this series, readers take an in-depth look at the many creatures that spend their lives completely--or partially--underwater, from fish and mammals that swim in the ocean to sea...