Define the following terms:
$(i)$ Mineral
$(ii)$ Ore
$(iii)$ Gangue

(N/A) $(i)$ Mineral: Most elements occur in nature in a combined state as minerals. The chemical composition of minerals is fixed.
$(ii)$ Ore: Minerals from which metals can be extracted profitably are known as ores.
$(iii)$ Gangue: The impurities (sand,silt,soil,gravel,etc.) present in the ore are called gangue.