4 c+d

Question 1

3 molecules which are cycled through ecosystems

Answer 1

-Oxygen
-Carbon dioxide
-Water

Question 2

Describe how carbon dioxide is cycled through an ecosystem

Answer 2

-Carbon dioxide is fixed through photosynthesis
- Respiration releases carbon dioxide
- Decomposition releases carbon dioxide
- Combustion releases carbon dioxide

Question 3

What detrimental impacts can sulfur dioxide have on the environment?

Answer 3

• Formed when fossil fuels containing impurities are burnt
• Sulfur dioxide can dissolve in water to form acid rain which can pollute water sources, cause damage to plants (deforestation) and cause breathing problems to humans and animals

Question 4

What detrimental impacts can carbon monoxide have on the environment?

Answer 4

• Carbon monoxide is formed from the incomplete combustion of fossil fuels
• Carbon monoxide binds irreversibly to haemoglobin which prevents it from carrying oxygen
• Too much exposure can cause unconsciousness and death

Question 5

5 greenhouse gases

Answer 5

• Water vapour
• Carbon dioxide
• Nitrous oxide
• Methane
• CFCs

Question 6

3 human activities that contribute to greenhouse gases

Answer 6

• Burning fossil fuels
• Deforestation
• Large scale livestock farming

Question 7

How do greenhouse gases leef to global warming?

Answer 7

• Greenhouse gases allow heat from the sun to enter the atmosphere
• The gases act as a “blanket” and trap the heat in the atmoshpere

Question 8

3 negative consequences of global warming

Answer 8

• Sea level rise caused by melting icebergs
• Disrupted farming and agriculture
• Increased spread of diseases in warmer climates

Question 9

Describe how sewage in waterways can affect aquatic life

Answer 9

• Waste from houses pollute the water
• Bacteria decompose faeces, using up oxygen
• Water becomes anoxic, many species including fish die
• Few species survive

Question 10

What is eutrophication?

Answer 10

• Fertilisers (nitrates + phosphates) leach into rivers
• Algal bloom
• Algae and water plants die
• Bacteria decompose dead algae plants
• Water becomes anoxic. Fish die. Biodiversity decreases