Presenter notes: Do not define anything yet. Open with a question the class can answer from memory: name an animal you would only ever see in the Terai, and one you would only ever see in the mountains. Rhino and yak come quickly. Then ask the question they cannot answer: what is stopping the yak from walking down? There is no fence and no border guard. Let them offer answers and do not correct any of them. The lesson is the answer, and it is better if they arrive wanting it.