Answer:
some of it I believe is the correct answer for that question
I think the answer is A..... ps c and d are the same
The compound formed by carbon would be very stable and need more energy to break than the sodium compound....
A closed system is a system that makes no physical or chemical exchanges with its environment. Of these systems provided as choices (tree, human, clock, car), only a clock does not make exchanges with the environment, except for energy.
Therefore, of that list, only a clock would be a closed system.
Hope that helped! =)
