Which of the following is a fossil fuel?
Silver
Gold
Iron
Coal
Which of the following is usually referred to as 'black gold' ?
(a) coke
(b) coal tar
(c) petroleum
(d) coal
Which of the following is not a fossil fuel?(a) coal(b) petroleum gas(c) biogas(d) natural gas
Since coal is a fossil fuel, the main source of coal is: