World 4 · How Birds and Bats Fly · 10 min · PRO
Bat wings
Hands covered in skin
PRO · Animal Movers
World 4: How Birds and Bats Fly is part of PRO
The first world of Animal Movers is free. PRO opens the other 20 lessons in 5 worlds — simulations, quizzes and all.
PRO includes
- All 60 labs — every world, every lesson
- Practice exams and certificates
$8.33/mo, billed yearly ($99.99) · or $39.99 monthly