Answers

2015-10-02T20:19:53+05:30
It is called black gold because when  we we dig it out ,it is black in colour.
it is worth a lot of money.
i hope this helps u...
0
2015-10-02T21:08:26+05:30
Because it black in colour and it is precious as gold .it should conserve.so,petroleum is called black gold

0