Answer:
D change in average temperature of a region
Explanation:
А seasonal change from spring to summer - these seasonal changes happen often and the organism will already be used to such changes
B a storm passes overnight - while this could have a significant impact on the ecosystem, the storm is not a long term change
С an earthquake - while this could have an impact on the ecosystem, this is a single event and is not considered a long term change
D change in average temperature of a region - this is a long-term change that will effect many aspects of the organisms lives. This includes food supply, need for shelter, water availability, energy requirements, etc.
