Select the correct answer.
why does a solid change to liquid when heat is added?
oa
the spacing between particles decreases.
o b.
particles lose energy.
oc.
the spacing between particles increases.
od. the temperature decreases.

the answer is A- the spacing between particles decreases. Because as you put heat on a solid such a ice the density of tht solid decreases and turn into a liquid (water)

when density of a solid decreases, the spacing between the particles decreases

In a way just think that the particles loosen up to the point where it no longer holds together as a solid.