Answer: allele/ gene / homologous
Explanation:
Fermentation
The electron transport chain gives off 32 ATP the kreb cycle gives off 2 and so does glycolysis. Fermentation happens in muscles or alcohol
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! =)
Trophic cascades are powerful indirect interactions that can control entire ecosystems