Final answer:
Classes of crises include natural disasters, financial crises, human-made disasters, and existential crises, each impacting society in distinct ways.
Step-by-step explanation:
Crises can indeed originate from various sources, affecting societies and individuals in numerous ways. The classes of crises mentioned include Natural disasters, such as hurricanes, earthquakes, and tsunamis, which have historically caused significant loss of life and property damage. Financial crises can lead to economic downturns with wide-ranging effects on employment and social stability. Human-made disasters, encompassing events like industrial accidents or warfare, result from human activities and can have devastating environmental and societal impacts. Lastly, Existential crises pertain to individual or collective feelings of meaninglessness or questioning life's purpose, which can be triggered by various personal or societal events.