(a) "Conserving energy is essential for sustainable development." Support the statement with suitable arguments.

(i) Energy is a basic requirement for economic development. Every sector of the national economy – agriculture, industry, transport, commercial and domestic- needs inputs of energy.

(ii) There is an urgent need to develop a sustainable path of energy development.

(iii) Promotion of energy conservation and increased use of renewable energy sources are the twin planks of sustainable energy.

(iv) Using non-conventional sources- solar, wind, bio-gas, geo-thermal etc.

(v) Non-conventional sources are renewable, eco- friendly, cheaper, and do not leave any residue.

(vi) India is adopting a cautious approach for the judicious use of its energy resources.

(vii) For example, as concerned citizens we can do our bit by using public transport systems instead of individual vehicles.

(viii) Switching off electricity when not in use, using power-saving devices and using non-conventional sources of energy.

(ix) It is felt that by conserving energy we will protect the delicate ecological balance.

(x) India is also improving energy efficiency.

(b) “Minerals are found in various forms and types, each having distinct properties.” Support the statement with suitable arguments.

(i) In igneous and metamorphic rocks, minerals form by cooling and solidification of lava in cracks, crevices, faults or joints. The smaller occurrences are called veins and the larger are called lodes. For example, major metallic minerals like tin, copper, zinc and lead etc.

(ii) In sedimentary rocks a number of minerals have been formed as a result of deposition, accumulation and concentration in horizontal strata. Coal and some forms of iron ore have been concentrated as a result of long periods under great heat and pressure.

(iii) Another group of sedimentary minerals include gypsum, potash salt and sodium salt. These are formed as a result of evaporation in arid regions.

(iv) Another mode of formation involves the decomposition of surface rocks, and the removal of soluble constituents, leaving a residual mass of weathered material containing ores. Bauxite is formed in this way.

(v) Certain minerals may occur as alluvial deposits in sands of valley floors and the base of hills. These deposits are called ‘placer deposits’ and generally contain minerals which are not corroded by water. Gold, silver, tin and platinum are most important among such minerals.

(vi) The ocean waters contain vast quantities of minerals, but most of these are too widely diffused to be of economic significance. However, common salt, magnesium and bromine are largely derived from ocean waters.