This lesson plan is for a 9th grade biology class on double circulation. It involves two activities where students will label a diagram of pulmonary circulation and systemic circulation. They will learn that double circulation is where blood passes through the heart twice, with pulmonary circulation moving blood from the heart to the lungs and systemic circulation moving blood to the entire body before returning to the heart. The lesson aims to develop students' factual, conceptual, and procedural knowledge of double circulation.