about twenty-five of the ninety-two natural elements are known to be essential to life. which four of these twenty-five elements make up approximately 96 percent of living matter?

it means there are 3 atoms of oxygen

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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