Juvenile literature Development Behavior Giant panda -- Owls Owls -- Penguins -- Sunshine Tiger -- Animal ecology -- Animal relationships -- Arithmetic Children's stories Climatology Earth Day Energy conservation Environmentalism Gliders (Aeronautics) -- Grover(Fictitious character: Henson) Hang gliders -- Hang gliding -- Helicopters -- Human -- Human ecology -- Human-plant relationships -- Infancy Lambs Light Parachutes -- Parachuting --