I'm only in middle school but i believe its coal.
It would be an physical change ; if you melt butter the butter goes from a solid to a liquid so therefore the physical state is changed.
"Increase Pressure " is the right answer. if you need help , let me know
The correct answer is D. A solid has a high to very high melting point, great hardness , and poor electrical conduction, this is a covalent network solid. This is because of the large amount of energy required to break these bonds, the said properties are exhibited by these solids.
