Which is the best evidence that rocks found deep underground were once exposed at the surface?

a
the rocks have been melted by a magma.
b
the rocks have been broken by faults.
c
the rocks have been weathered by water.
d
the rocks have been folded by pressure.

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.

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.