Cycles and Human Impact

Question 1

What is the importance of CO2 in the atmosphere ?

Answer 1

It traps heat in the atmosphere

Question 2

How can a volcanic eruption affect the Earth’s atmosphere ?

Answer 2

Its ashes can block sunlight, and in extreme cases cause global cooling

Question 3

Define combustion of fossil fuel

Answer 3

Burning of coal, oil, and natural gases

Question 4

Define deforestation

Answer 4

Cutting down large areas of trees

Question 5

What is the main issue associated with the burning of fossil fuel ?

Answer 5

Global warming

Question 6

Other than adding CO2 to the atmosphere, how does combustion of fossil fuel affect the atmosphere ?

Answer 6

It releases nitrogen and sulfur in the atmosphere, which forms acid rain if combined with water in the atmosphere

Question 7

How do humans affect the water cycle ?

Answer 7

• Agriculture
• Overuse of aquifers (ground water)
• Urbanization

Question 8

What are the importance of the nitrogen cycle ?

Answer 8

• 78% of air is nitrogen
• All organisms need nitrogen
• Nitrogen is present in DNA and RNA and in amino acids (proteins)

Question 9

How do humans affect the nitrogen cycle ?

Answer 9

• Humans add extra nitrogen in the cycle due to fertilizers and mineral wastes that runoff into lakes and river
• Too much nitrogen can cause eutrophication