Final answer:
Iranians must ration supplies due to economic and environmental factors, including water via the qanat system and economic resources controlled by government central planning. Rationing in Iran is a response to challenges such as desert climate and fluctuating commodity prices which affect their oil and gas-dependent economy.
Step-by-step explanation:
Iranians are required to ration their supply of various essential resources, much like Americans and other countries did during World War II. In that time, governments controlled the purchasing of products like gasoline, food items, clothing, and other goods due to the necessity of allocating these resources to military efforts. Similarly, Iranians today implement rationing as a response to different economic and environmental challenges. For instance, Iran, with its largely desert climate, has developed an ancient system of qanats for water rationing, which is essential for redirecting the limited water supply from the mountains to urban centers for agricultural and domestic use.
Moreover, due to fluctuating commodity prices and an economy heavily dependent on oil and natural gas, Iranians face pressure to manage their resources efficiently. The government's control over major businesses, including the oil and gas industry, allows for a measure of central planning in the rationing of economic resources, aiming to maintain stability and support a growing manufacturing base for a more diversified economy.