Both indicate the temperature at which the solid and liquid states of a substance are in equilibrium would be your answer.
This is beacause the melting point of a substance is the same as the freezing point of a substance. At this particular temp, the substance can be either a solid or a liquid.
hope this helps!
Spontaneous at low temperatures.
The answer is A. Ne. You can separate the elements in the other three choices through chemical changes (dissociation, ionization, electrolysis, etc.), but in order to separate the components of Ne, you would need a nuclear reaction (to decompose the nucleus) or a physical change (to strip the nucleus of its electron cloud).
The molar mass is 64.07g/mo