Mendel discovered Hereditary
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! =)
Answer:
9 brains
Explanation:
No explanation, but you can fact check this by looking it up :)