World 8 · Minerals & strata · 9 min · PROWhich came first?
Superposition and cross-cutting relationships
PRO · Plate Tectonics
World 8: Minerals & strata is part of PRO
The first world of Plate Tectonics is free. PRO opens the other 46 lessons in 7 worlds — simulations, quizzes and all.
PRO includes
- All 26 labs — every world, every lesson
- Practice exams and certificates
$8.33/mo, billed yearly ($99.99) · or $39.99 monthly