(a) How is energy a basic requirement for economic development? Explain with examples.

(i) Every sector of national economy needs inputs of energy.

(ii) The economic development plans implemented since independence necessarily required energy to remain operational.

(iii) As a result, consumption of energy in all forms has been steadily rising.

(iv) Industries cannot run without energy

(v) Transport also needs energy.

(b) How do minerals occur? Explain with examples.

(i) Minerals are usually found in ores. The term ore is used to describe an accumulation of any mineral mixed with other elements.

(ii) Minerals are found in Igneous and Metamorphic rocks: Minerals may occur in the cracks, cervices, faults or joints. The smaller occurrences are called veins and the larger are called lodes. Major metallic minerals like tin, zinc and lead etc. are obtained from veins and loads.

(iii) Sedimentary rocks: In these rocks a number of minerals occur in beds or layers. They have been formed as a result copper of deposition, accumulation and concentration in horizontal strata. Eg. coal and some forms of iron ore.

(iv) Occur as alluvial deposits: Certain minerals may occur as alluvial deposits in sands of valley floors and the base of hills. These deposits are called ‘placer deposits’. Gold, silver, tin and platinum are most important among such minerals.

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