Step-by-step explanation:
Terai, Hilly and Himalayan region are interdependent on each other. Glaciers and rivers originated from Himalayan region flow towards south. It comes to hill and then Terai and bring fertile muds with it. The fertile land before and rivers help in the irrigation and growing crops in Terai. The grown crops are exported to all over the nation. Also people from Terai and Himalayan comes to Hilly region for getting good education and job. Himalayan region also provides wool and milk. Many tourists come to see the mountains located in the Himalayan region and the collector taxes is used in developing the whole nation. In this way different regions are interdependent on each others.