Concept:Environmental balance means the natural interactions that keep ecosystems stable and self-regulating.
Explanation:The hydrological cycle and the carbon cycle are important natural cycles that recycle water and carbon.
These cycles support life and help to maintain a balanced environment.
Food chains and food webs represent the feeding relationships between organisms in an ecosystem.
They help control energy flow and population numbers, so they also maintain ecological balance.
All of these processes are biological or ecological in nature.
The earthquake cycle is caused by movements inside the Earth’s crust.
It is a geological process rather than an ecological process.
Therefore, it is not part of environmental or ecological balance.
Answer:D. earthquake cycle