It absorbs heat and give off thermal energy just saying i think its right
True it is based on a set of observations
Heat of Fusion is defined as the energy required to turn a liquid into a solid, or said phase changing latent heat. In this case the only choice that represents that phase change is (1). Where the heat removed to turn a liquid of a substance into it's solid form is instead added to excite the bonds and liquify it. Yet, heat of fusion (s) ->(l)
is still the same as going from liquid to solid just one is adding and the other is removing, respectively.
