NCERT VI Social Sciences

Air, water, piece of rock, sheet of aluminium, mirror, wooden board, sheet of polythene, CD, smoke, sheet of plane glass, fog, piece of red hot iron, umbrella, lighted florescent tube, wall, sheet of carbon paper, flame of a gas burner, sheet of cardboard, lighted torch, sheet of cellophane, wire mesh, kerosene stove, sun, firefly, moon.

but what is the question?