Answer: C - introduction of an unchecked invasive species.
E- massive flooding.
Explanation:
The catastrophic event can be define as the event which can cause huge damage to the living and non-living factors of the ecosystem. It can make the environment unsuitable for the survival of the living beings and can become the cause of mass extinction.
C is the correct option because the introduction of invasive species can reduce the population of members of the native species if the invasive species compete with the native species for resources.
E is the correct option because the massive flood will wiped out the living beings and can destroy the landscape and property of the region where it occurs.
