23 books • 7 series
Dirt Bikes (Start Your Engines!)
Sink vs. Float (Science Showdowns)
Magnets Attract vs. Magnets Repel (Science Showdowns)
Renewable Energy vs. Nonrenewable Energy (Science Showdowns)
Push vs. Pull (Science Showdowns)
Influential People Pack C of 2 (Influential People)
Influential People Pack B of 4 (Influential People)
Unique Animal Adaptations Poison Dart Frogs
Area 51 Alien and UFO Mysteries (Aliens)
Unique Animal Adaptations (Unique Animal Adaptations)
Aliens (Aliens)
Poison Dart Frogs (Unique Animal Adaptations)
Aliens Area 51
Bulldozers
Dirt Bikes
Front-End Loaders
Cranes
Excavators
Chadwick Boseman (Influential People)
Excavators (Construction Vehicles (Pop))
Front-End Loaders (Construction Vehicles (Pop))
Bulldozers (Construction Vehicles (Pop))
Cranes (Construction Vehicles (Pop))