Sustainability
50 exam-style questions with answers for 3.6 Sustainability in AQA A-level Environmental Science (spec 7447). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, Five Degrees, Associations, or read every question and answer below. Not official AQA material.
All 50 questions and answers
Question 1
Explain what is meant by negative feedback, using an example. [2 marks]
Answer:A change causes a response that reduces the change. For example, warming increases low cloud, which raises albedo and cools the surface.Question 2
State three principles of the circular economy. [3 marks]
Answer:Any three from: cycling of materials, renewable energy, design for end-of-life reuse, separating technical and biological materials, waste of one process as the raw material for another.Question 3
Define ecological footprint and biocapacity. [2 marks]
Answer:Ecological footprint: the area needed to supply a population’s resources and absorb its wastes. Biocapacity: the area of productive land and sea available to do this.Question 4
Define the term ‘dynamic equilibrium’. [1 mark]
Answer:A state where inputs and outputs balance, so a system stays stable despite continuous change.Question 5
Explain why diverse systems are more resistant to change. [2 marks]
Answer:More interspecies relationships and a stable food web mean the loss of one species has less effect.Question 6
Explain why most natural processes occur at low temperatures. [2 marks]
Answer:Enzymes lower activation energy, for example biological nitrogen fixation compared with the high-temperature Haber process.Question 7
Contrast linear and circular systems. [2 marks]
Answer:Linear systems use resources then dispose of waste. In circular systems the waste of one process is the raw material for another.Question 8
Explain why natural waste products do not cause toxicity. [2 marks]
Answer:They are biodegradable and broken down into non-toxic products used by other processes.Question 9
State how solar energy drives natural cycles. [2 marks]
Answer:It powers the hydrological, carbon and nitrogen cycles, atmospheric circulation and thermohaline circulation.Question 10
Explain how a country’s ecological footprint can exceed its biocapacity. [2 marks]
Answer:High population and per-capita consumption mean demand exceeds the area available to supply resources and absorb waste.Question 11
Outline two circular economy approaches to waste. [2 marks]
Answer:Reduce, reuse, repurpose and recycle, and separate biological and technical materials.Question 12
Explain why optimum rather than maximum production features in the circular economy. [2 marks]
Answer:Natural systems leave a surplus that supports pollinators, seed dispersers and decomposers.Question 13
State two ways carbon footprints can be reduced. [2 marks]
Answer:Use renewable energy and reduce energy demand, for example by insulation.Question 14
Explain the role of feedback in the hydrological cycle. [2 marks]
Answer:Higher temperature increases evaporation, which increases precipitation, a negative feedback.Question 15
Describe how afforestation supports sustainability. [2 marks]
Answer:Trees sequester carbon, reduce runoff and erosion, and provide habitat.Question 16
Define the term ‘circular economy’. [1 mark]
Answer:An economy where materials are cycled and waste is designed out, mimicking natural systems.Question 17
State what the Living Planet Index measures. [1 mark]
Answer:Population trends of thousands of vertebrate species, as a measure of global biodiversity.Question 18
Explain why fossil fuels are unsustainable. [2 marks]
Answer:They are non-renewable and used faster than they form.Question 19
Explain why mineral use is often linear. [2 marks]
Answer:Minerals are dispersed or mixed after use, so recovery and reuse is difficult.Question 20
Describe cradle to cradle design. [2 marks]
Answer:Products are designed so components can be reused or recycled at end of life.Question 21
Describe how ecosystems can be included in urban planning. [2 marks]
Answer:Green roofs, parks and wildlife corridors conserve wildlife and improve quality of life.Question 22
Explain how renewable energy supports the circular economy. [2 marks]
Answer:It replaces finite fuels and supports low-temperature manufacturing.Question 23
Explain why agroecosystems are less resistant to change than natural systems. [2 marks]
Answer:They have low diversity, so pests and disease spread quickly.Question 24
Describe a positive feedback involving permafrost. [2 marks]
Answer:Warming melts permafrost, releasing methane, which causes more warming.Question 25
Describe a negative feedback involving photosynthesis. [2 marks]
Answer:More CO2 increases photosynthesis, removing CO2 and slowing warming.Question 26
Explain how population regulation shows dynamic equilibrium. [2 marks]
Answer:Density-dependent factors reduce growth near carrying capacity, then the population recovers.Question 27
Explain why natural systems use few elements. [2 marks]
Answer:A small number of elements build monomers and polymers such as carbohydrates and proteins, so wastes are reusable.Question 28
State two ways to reduce an ecological footprint. [2 marks]
Answer:Lower consumption, use renewable energy, adopt sustainable agriculture.Question 29
Describe how pollution control moves towards non-release. [2 marks]
Answer:Treating waste after production is replaced by changing technology, such as fuel cells instead of combustion engines.Question 30
Explain how food waste can be part of a circular economy. [2 marks]
Answer:Anaerobic digestion produces biogas and compost returns nutrients to farmland.Question 31
Define the term ‘sustainability’. [1 mark]
Answer:Meeting the needs of the present without compromising the ability of future generations to meet their own needs.Question 32
State the three pillars of sustainability. [3 marks]
Answer:Environmental (1); social (1); economic (1).Question 33
Define the term ‘positive feedback’. [1 mark]
Answer:A process in which a change causes further change in the same direction, moving the system away from its original state.Question 34
Define the term ‘natural capital’. [1 mark]
Answer:The stock of natural resources and ecosystems that provide goods and services to people.Question 35
Define the term ‘ecosystem services’ and give one example of a regulating service. [2 marks]
Answer:The benefits people gain from ecosystems (1); eg climate regulation, flood control, pollination, water purification (1).Question 36
Define the term ‘carbon footprint’. [1 mark]
Answer:The total greenhouse gas emissions, expressed as carbon dioxide equivalent, caused by a person, product, organisation or activity.Question 37
Explain what is meant by ‘ecological overshoot’. [2 marks]
Answer:Human demand on nature exceeds the biosphere’s biocapacity (1); resources are used faster than they regenerate, so natural capital is depleted and waste accumulates (1).Question 38
State one limitation of the ecological footprint as a measure. [1 mark]
Answer:Any one: uses averages and assumptions; does not include all impacts such as biodiversity loss or pollution; data may be unavailable or inaccurate; hard to compare countries fairly.Question 39
Describe the waste hierarchy. [2 marks]
Answer:Preferred order of waste management: reduce, reuse, recycle, recover energy, then dispose (1); the aim is to keep materials in use and minimise landfill (1).Question 40
Distinguish between open and closed systems, with an example. [2 marks]
Answer:Open systems exchange both matter and energy with surroundings (1); closed systems exchange energy but not matter, eg Earth as a whole (1).Question 41
State two benefits of the circular economy to businesses. [2 marks]
Answer:Any two: lower raw material and waste disposal costs; reduced exposure to resource price rises; new markets for repair and recycling; improved reputation.Question 42
Describe industrial symbiosis. [2 marks]
Answer:Waste or by-products of one industry become the raw materials of another (1); eg in Kalundborg, Denmark, waste heat and steam from a power station are used by neighbouring industries (1).Question 43
Explain how product design can extend the life of products. [2 marks]
Answer:Modular designs and standard parts make products easy to repair and upgrade (1); durable materials and designs for disassembly allow reuse and recycling at end of life (1).Question 44
Explain why energy efficiency supports sustainability. [2 marks]
Answer:Less fuel is used, so fossil fuel reserves last longer (1); lower greenhouse gas and pollutant emissions (1).Question 45
Explain the role of decomposers in nutrient cycling. [2 marks]
Answer:Break down dead organic matter and waste (1); release nutrients such as nitrates and phosphates back to the soil for plants to reuse (1).Question 46
Explain why population growth can increase ecological footprints. [2 marks]
Answer:More people need more food, water, energy and land (1); more waste is produced, increasing demand on biocapacity (1).Question 47
Explain how deforestation can be a positive feedback in climate change. [3 marks]
Answer:Forest loss reduces carbon uptake by photosynthesis and burning releases CO2 (1); more CO2 increases warming and drought (1); drier, hotter conditions increase fires and tree death, causing more forest loss (1).Question 48
Explain how carbon trading (cap and trade) aims to reduce emissions. [2 marks]
Answer:A cap sets a maximum total emission and permits are issued or sold (1); companies that cut emissions can sell spare permits, giving a financial incentive to reduce pollution (1).Question 49
Explain why driving less reduces a person’s carbon footprint. [2 marks]
Answer:Less fossil fuel is burned, so fewer CO2 emissions (1); transport is often a large part of a personal footprint, so walking, cycling or public transport lowers it (1).Question 50
Explain why waste is described as a resource in a circular economy. [2 marks]
Answer:Waste materials can be reused, remanufactured or recycled as inputs (1); this keeps materials in use for longer and reduces extraction of raw materials (1).