World 4 · Why Leaves Change Colour · 10 min · PRO
Autumn chemistry
Why green fades first
PRO · Tree & Forest Lab
World 4: Why Leaves Change Colour is part of PRO
The first world of Tree & Forest Lab 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