Which of the following is the least polluting fuel for vehicles?

Coke is used in the manufacturing of which of the following metals?

What is the product of decomposition of animal and plant waste in the absence of air?

In LPG cylinder how is the gas liquefied?

Where was the world's first oil well drilled?

Fuels are present in which of the following forms?
A) Solid
B) Liquid
C) Gas

Which gas is obtained during the processing of coal?

Naphthalene balls are obtained from which of the following materials?

Which was used in railway engines to produce steam to run the engines in earlier days?

Which is the main source of energy for all living beings on earth?