Whether an element is classified as a major or as a trace mineral is determined by

Calcium, magnesium, phosphorus, potassium, chloride and sulfur are all examples of the major minerals and these are the minerals a body needs in large quantity as opposed to include iron, copper, zinc, manganese, fluoride, selenium and cobalt, which are all trace minerals and are needed in very little quantity.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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