Overconsumption – situation where resource use has outpaced the sustainable capacity of the ecosystem. ...
Overpopulation – too many people for the planet to sustain. ...
Acid rain.
Biodiversity loss.
Deforestation.
Desertification.
Global warming/climate change.
Habitat destruction.
source - wikipedia.org
Scientists so far haven’t managed to figure that out .
If ecology is an option than it is that.
Answer:
2)
Explanation:
The positive control is the treatment where bacteria grew without lead. Since positive control indicates the presence of bacteria in the experimental conditions, it is possible to confirm that they only death in presence of this metal. However, it is important to note that it is imperative to repeat this experiment three times and also to include a negative control in order to confirm these results.