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How do human pollute water?
- Humans pollute water with:
- Sewage
- Fertiliser
- Toxic chemicals
- Causing high level of nitrates in the water
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How do humans pollute the air?
- Humans pollute the air with:
- Smoke and gasses such as sulphur dioxide, which contributes to acid rain
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How do humans pollute land?
- Humans pollute land with:
- Toxic chemicals such as pesticides and herbicides, which may be washed away into the water
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What is the effect of large scale deforestation?
- Deforestation has:
- Increased the release of carbon dioxide into the atmosphere
- Reduces the rate at which carbon dioxide is removed from the atmosphere, by photosynthesis
- Reduces biodiversity due to loss of food and habitat
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Why has deforestation occurred?
- Deforestation has occurred so that:
- Crops can be grown to produce ethanol-based biofuels
- There can be an increase in cattle and rice fields to provide more food
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What is the disadvantage of the increase production of cattle and rice fields?
Cattle and rice growing produce methane, which has led to an increase of methane in the atmosphere
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Why is the destruction of peat bogs bad?
The destruction of peat bogs and other area of peat result in the release of carbon dioxide into the atmosphere; due to the decay of the compost by micro organisms
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How is carbon dioxide sequestered?
Carbon dioxide is sequestered as carbon dioxide is removed from the air by plants and by dissolving in oceans, rivers and lakes
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What is meant by greenhouse gasses?
This is the level of carbon dioxide and methane increasing in the atmosphere
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What will happen if there is a slight increase in the earths temperature?
- An increase in the earths temperature may:
- Cause big changes in the earths climate
- Cause rise in sea levels
- Reduce biodiversity
- Cause change in migration patterns eg. Birds
- Changes in the distribution of species
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Describe the process of ethanol-based fuels?
- Ethanol-based fuels can be produced by fermentation
- Glucose is produced from maize starch by the action of carbohydrase
- Microorganisms (yeast) respire anaerobically to produce the ethanol, using sugars from crops as the energy
- Ethanol is extracted by distillation
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How can the efficiency of food production be improved?
The efficiency of food production can be improved by reducing the number of stages in food chains
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How can we produce meat more efficiently?
- We can produce meat more efficiently by:
- Preventing the animals from moving so energy isn't wasted on movement
- Controlling the temperature of their surroundings so that energy from food isn't wasted to maintain body temperature
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What is meant by sustainable food production?
This is a method of producing food which can be sustained over time without destroying the fertility of the land or ocean
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How are fish stocks in the ocean monitored?
- Fishermen can only remove a strict allocation of fish per year
- Fishermen must use certain sized nets to avoid catching small, young fish.
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What is mycoprotein?
Protein from fungus
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What is Fusarium?
- Fusarium is grown to produce mycoprotein.
- This is a protein-rich food suitable for vegetarians
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How is Fusarium grown?
The fungus is grown aerobically on cheap sugar syrup and the biomass is harvested and purified
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What factors must be controlled in large industrial fermenters?
- pH levels
- Oxygen levels
- Temperature
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