Answer:
b.the influence of humans on a natural system can have unpredictable negative impacts
Explanation:
The situation described best illustrated the fact that the disturbance of natural ecosystem by humans can have unpredictable negative impacts.
Option c is incorrect because human alteration of the ecosystem needs to be continuously studied to avoid ecological disasters.
Option d is incorrect because alteration of the ecosystem does not always end up in the pollution of the ecosystem and loss of finite resources.
While human alteration of the natural ecosystem often have long term negative impacts, many of these impacts can not be predicted until they happen. This makes option b to be more complete than option a.
The correct option is b.