Which of the following demonstrates forces that change the motion of an object?

the answer would be A :)

Explanation:

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.

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.