Chemistry is often called the science because it involves the study of the materials in the universe and the changes these materials undergo

Central

Explanation:

Chemistry is often called the central science because of connects the physical sciences, life sciences and applied sciences.

Chemistry is the study of matter and changes undergone by matter. This makes chemistry to occupy a central place in many scientific disciplines including medicine, engineering, pharmacy, geology etc. Basic knowledge of chemistry is usually required by experts in these disciplines.

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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