Answer:
The correct answer is unnatural occurrences.
Step-by-step explanation:
The unnatural occurrences refer to the catastrophic incidents created due to human activities that can impart deleterious effects on the ecosystem. These activities exhibit the most impact on a specific ecosystem. This may comprise forest fire, deforestation, road building, mining explosions, and others.
These activities are considered harmful as it may lead to the destruction of various species because of the damage resulting to the non-living physical environment.