Constructivist Learning Approach in Science Teaching

Constructivist learning approach is a pupil-centered . Constructivist learning approach has been applied in eigteenth century . Giambattista Vico, Bruner, Piaget, von Glasserfeld and Vyogotsky are whale at this field. Giambattista Vico said that one only knows something if one can explain it. Constructivist processes are prior knowledge ,real and authentic problems , constructivist curriculum, cognitive conflict and social context, constructivist assesment and the teacher's role in education. In constructivist learning and teaching, knowledge mustn't give directly from teacher to studets. Students must obtain knowledge him/herself as researching or taking-giving information etc. Teacher/Instructor is a coach , analyzer and guide. Students/Pupils who cannot be obtain knowledge and evaluate him/herself. Pupils have interpretations about unit, problem, theme or something like that. The learning environment has an active role in constructivist approach. My question:              - Who arrange the learning environment, pupils or teachers? And why?
                                                  - If pupils prior knowledge or experiences are wrong or incomplete how   can we fix it ?
                                                  -How much clues could we give to pupils in constructivist learning?
                                                  -How much  be independent must pupils in classroom?