Q: Fact 1: Phase changes do not change mass. Fact 2: Melting, freezing, condensation, and evaporation are examples of phase changes. Given the two facts above, melting matter does not change its ?

OPTIONS:
[+] crust.
[+] metal.
[+] mass.
[+] O3.
[+] heat.
[+] cycles.
[+] energy.
[+] liquid.
The answer is:
mass