1. compare and contrast substances and mixtures. give
two examples of each.

A substance is a sample of a specific type of matter, such as:

-water

-dirt

-

A mixture is a combination of two or more contrasting substances, some mixtures fully combine to create a new substance and some mixtures simply create combinations such as:

-A mixture of dirt + water creates mud which is an example of a new substance

-A mixture of cheese + ham + bread creates a sandwich which is an example of a combination

Hope this helps :)

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.