Petra means ---------------

The inner surface of the solar cooker and the outer surface of the containers are painted ----------------

Which one is example for renewable resources ?

All water-bodies on the earth such as, rivers, lakes, oceans etc., together form-------------

Biogas mainly consists of -------------

The materials decomposed to non toxic, non poisonous substances by the action of certain ----------------

The moving air is called -------------------

Flowing water possesses -------------- energy.

Which  of  the following is not a fossil fuel?

Which one is example for water pollutants?