Question

question 9
2 pts
air pollution is always caused by human activities.
true
false
question 10
2 pts
low oxygen, dead zones are an issue in how many lakes and streams in north america,
europe and asia?
20%
80%
50%

Explanation:

Question 9

Air pollution can be caused by natural phenomena like volcanic eruptions (releasing ash, gases) and wildfires (producing smoke, particulate matter) in addition to human - made sources such as industrial emissions and vehicle exhaust. So, the statement "Air pollution is always caused by human activities" is incorrect.

According to environmental research, low - oxygen dead zones are a significant issue in about 50% of lakes and streams in North America, Europe, and Asia. This is due to factors like nutrient runoff (e.g., from agricultural fertilizers) leading to algal blooms, which then decompose and consume oxygen in the water.

Answer:

B. False

Question 10