The correct answer is C. Climate change
Step-by-step explanation:
Long-term environmental changes occur as major events affect the environment and ecosystems indefinitely. These events differ from short-term environmental changes because the effect of short-term environmental changes is mainly temporary. Also, long-term changes are usually gradual.
Climate change is an example of long-term environmental changes because this implies indefinite and major changes in weather patterns and ecosystems. For example, it is believed climate change will decrease the amount of ice in Earth, change sea level, and lead to the extinction of dozens of species. This does not occur with events such as el niño or a small asteroid impact that affect the environment for a short time and do not imply major changes.