Indicator 2a.ii

The evidence shows an intentional sequence where student tasks build in sophistication across the unit: in Lesson 2 students 'construct their first written argument with scaffolding' as a formative checkpoint [E2], progress to predictive arguments around competing claims in Lesson 5 [E3], then to revised evidence-based arguments evaluating alternate arguments in Lesson 9 [E6], culminating in an independent summative argument on notebook paper in Lesson 10 [E4]. The numbered lesson-level performance expectations (Lessons 1, 2, 3, 5, 6, 9, 10, 11) with escalating SEPs—from developing initial models [E9][E11] to constructing explanations using molecular models to predict outcomes [E7]—demonstrate a designed, increasing-complexity arc. The teacher guide explicitly frames early tasks as scaffolded/formative and later ones as summative, confirming the intentional progression [E10][E2][E4].