1. quartz crystals normally used in quartz clocks etc. is chemically a. silicon dioxide b. germanium oxide c. a mixture of germanium oxide and silicon dioxide d. sodium silicate 2. which of the gas is not known as green house gas? a. methane b. nitrous oxide c. carbon dioxide d. hydrogen

1.  A.  silicon dioxide

2. D.  Hydrogen

Explanation:

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.