Answer:
They all have molecules in motion,
you may not think this about solids but the molecules are packed so closely together there is no room to get past each other.
for a liquid the molecules are packed densely but are loosely place, giving them the space to slip past each other, making it possible to form to what ever the liquid is in.
for gas the molecules are not packed so loosely that it is not a definable shape, but can be compressed