Questions What is the main point of the passage?
Ultraviolet rays can cause chemical reactions.
Van Gogh was the most famous painter of the Impressionist era.
Art conservationists can always restore art.
Artists' paints can eventually damage the canvasses.
201A

Artists' paints can eventually damage the canvasses.

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.

if it's not useful, feel free to report for mistake in answer.