Question

petroleum is known as the BLACK GOLD. give reason. ( atleast 6 to 8 lines).

Answer 1

Because it is expensive as gold
It is difficult to obtain

Answer 2

We all know that gold is a source of rich economy and profit.Everyone values gold.It makes you rich and gives you power.Petroleum has also became as valuable as gold nowadays.Due to its excessive use its cost has increased and it is important source of economy for countries like Arab,Israel,etc.
If you open a petrol station,you will get rich within a month.So petroleum is termed a BLACK GOLD due to its value which will one day may surpass gold.