Questions

The statement "A communist government is led by one political party" is what best defiines a communist government. Here in this type of government, the power is in the hands of the one political party and it only controls the political and economic systems of the country/state.

Iran is an important oil-producing region in the Middle East. Abadan on the Abadan island has one of the largest refineries in the world. 

Appropriations are annual decisions made by Congress about how the federal government spends some of its money. In general, the appropriations process addresses the discretionary portion of the budget – spending ranging from national defense to food safety to education to federal employee salaries, but excludes mandatory spending, such as Medicare and Social Security, which is spent automatically according to formulas.

Hence, congress grants funds to federal agencies and programs during the appropriations process.

Air is said to be saturated when it contains the maximum content of water vapour.

China has been by far the biggest coal producing country over the last three decades. The country produced about 3.6 billion tonnes (Bt) of coal in 2012 accounting for over 47% of the world's total coal output.

Both of them are relation ship constraints