With strong flippers and shark-like teeth, Mosasaurus once ruled the oceans. This sea reptile used to swim all over the world. Now, it captures the interest of readers. Take struggling and reluctant readers on a journey exploring this Cretaceous marine reptile's features, behaviors, and the ocean environment it lived in. With expertly leveled text, action-packed imagery, detailed maps, timelines, and other infographics, students will love this hi-lo nonfiction chapter book. Includes a table of contents, glossary with pronunciations, further resources, and an index to enhance comprehension.