1. A mudslide wipes out the side of a thriving hill: This is negative as many trees and other organisms will get destroyed.
2. A volcano erupts, covering the nearby land with lava: This is negative as molten and extremely hot lava can cause serious damage to its surroundings.
3. A forest is rapidly growing new plant life: This is positive because new plants are being grown.
4. Humans remove wolves from a national park to protect surrounding homes: This is positive for humans because humans will be safe but it is negative for the eco system as removal of wolves can upset the eco system cycle.
5. A dam is built in the middle of a river ecosystem to supply water to a nearby town: This is positive for humans as a new water resource is being developed for humans but negative for aquatic organisms as the dam can hamper their ecosystem and can cause pollution in water.