Questions

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. 

Both of them are relation ship constraints

Biological Control: This method is very effective. One pest is destroyed by another organism. For example the aphids are killed by lady beetle. The prickly pear is eradicted by cochineal insect. Here the advantage is, one does not use harmful chemicals which may get into the host plants.

The atmosphere is a mixture of several gases. Nitrogen is the most abundant gas in the atmoshere and oxygen is next to it. It is 78% in the atmosphere and 21% is oxygen. Remaining 1% is all other gases like argon, hydrogen, neon, etc...

The study of flags is called Vexillology and the art of flag design is called as Vexillography. The man who studies flags is called as Vexillologist.

A command economy types of government decide which goods would be produced without any interference of the public.

Command economy ran in Germany during the rule of Adolf Hitler. 

A command economy tends to exist under a socialist government that provides a lot of regulation.