One or more substances changing into one or more substances is an example of a

Hello There!

This is called a "Chemical Change"

A chemical change is when the composition of a substance changes. There are many signs of chemical changes. When a chemical change occurs, you can see a change in color. When a new color is visible that means that a new substance has been created. There also is a new smell "odor" this hints that a new substance has been formed.

i think so it’s will be b yes i believe its

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.