Which of the following describe(s) the changes, on a molecular level, when a solid melts?Select one:
a. The molecules become more widely separated.
b. The molecules acquire greater freedom of motion.
c. The molecules collectively no longer have a shape of their own.
d. The average kinetic energies of the molecules are greater.
e. All of these are true

Solids have definite crystal structures in which molecules maintain a certain and fixed distance with each other. Due to this restriction, molecules have very lower degrees of freedom.
In liquid, restriction around a molecule is lesser as compared to solids. Due to this molecules can move more freely as compared to solids and thereby possess higher degrees of freedom.
For a same substance, liquid form possess higher temperature than it's solid form. As average kinetic energy is proportional to temperature therefore liquid molecules have higher kinetic energy than solid molecules.
We know that liquids and gases do not have particular shape. Their shape depends on shape of their container.

So, all of the statements are true.