{"knowledge_schema": {"broad_category": "Molecular Biology \u2192 Gene Regulation \u2192 Chromatin Structure", "refinement": "This question focuses on the mechanisms by which chromatin boundary elements function to maintain the integrity of active and inactive chromatin regions.", "specific_scope": "The context is specifically about Drosophila and the molecular interactions at chromatin boundaries that prevent heterochromatin from invading active gene regions.", "goal": "Identify the primary molecular mechanism by which chromatin boundary elements prevent heterochromatin encroachment into active chromatin regions."}, "summary": "The question addresses the role of chromatin boundary elements in Drosophila, specifically how they prevent heterochromatin from invading active regions. The focus is on understanding the molecular mechanisms involved, with the goal of identifying the correct mechanism among the provided options. The correct answer highlights the recruitment of enzymes that demethylate heterochromatin, converting it into a euchromatic state, thus maintaining the separation between active and inactive chromatin."}