Answer:
C. Scale
Step-by-step explanation:
Scientists studying the effect of climate change can make use of wildfires as a simple case study.
Climate change is a global phenomenon because climate have predictable global patterns. Climate is highly affected by the global circulation and movement of air masses from one place to another.
If an activity in America such as burning fossil fuels is on the rise, the effect would not only be localized to that part of the world alone, agents of climates will randomly disperse the burden through a world wide global circulation pattern. This can be felt on a small scale by increasing wildfires in Australia.