A real classroom limit of scaffolding is:

1. Scaffolding starts with individual guidance matched to each learner. 2. In a large class, the teacher has little time for each student. 3. Teachers may cut parts of lessons or give each student less time. 4. So large classes are a key practical limit. **Why not the others:** The other three are misconceptions: help is meant to fade as pupils improve, scaffolding must start from the child's existing knowledge, and more able peers can scaffold too. _Source: Wikipedia, "Zone of proximal development", section "Challenges" (revision 1365068534)_