How to Answer a 20-Mark Question (AQA A Level Geography): Revision Note
Exam code: 7037
What is a 20-mark question?
The 20-mark question, often called a "20-marker", is the extended essay at the end of each section of both Paper 1 and Paper 2
You will answer three on each paper
These essays carry 60 of the 120 marks (50%)
You have about 25 minutes to plan and write it, with no figures to interpret, so your own knowledge and argument provide the evidence
Once each exam series, a question on Paper 1 or Paper 2 links content from different parts of the specification, and this is often a 9-mark or 20-mark question
The question at a glance
Marks | 20 |
Where it appears | the last question in each section |
Suggested time | about 25 minutes, including planning |
Suggested length | about 500–550 words |
Assessment objective 1 | 10 marks |
Assessment objective 2 | 10 marks |
Command phrases and assessment objectives
These questions often use command phrases such as:
"assess"
"evaluate"
"to what extent"
"discuss"
"analyse"
All of these command phrases need an argument that reaches a clear judgement
Past paper questions include:
“With reference to one or more coastal environments that you have studied, assess the potential impact of climate change on the development of landforms.” (Paper 1, June 2024)
“‘The Hazard Management Cycle is useful in minimising the impact of wildfires.’ Evaluate this view with reference to a wildfire event that you have studied.” (Paper 1, June 2024)
“‘Global governance of the global commons has a direct impact on your life and the lives of people across the globe.’ Critically assess the extent to which you agree with this statement.” (Paper 2, June 2024)
“‘Urban regeneration in Britain since 1979 has evolved to feature more dimensions of sustainability.’ To what extent do you agree with this statement?” (Paper 2, June 2024)
The question tests two assessment objectives (AOs) equally:
AO1 (10 marks): what you know, meaning knowledge and understanding of places, concepts, processes and change
AO2 (10 marks): what you do with it, meaning applying that knowledge through analysis, evaluation and judgement
Half the marks are for AO2, so a case study you have learned by heart cannot carry the essay on its own
How much should I write?
Spend about 25 minutes on each essay, including about 3 minutes of planning
Aim for about 500–550 words, as writing much more takes time from your other essays
Develop a few points fully rather than covering many points briefly
Full marks are possible within the answer space on the paper, so a longer essay is not automatically a better one
How is a 20-mark question marked?
This is a levelled response question, so each point you make doesn't equal a mark
The examiner reads your whole essay and decides which level it best fits
The examiner then places it within that level's mark range
An essay doesn't have to be perfect to get full marks
The four levels
Level 4 (16–20 marks)
Detailed, accurate knowledge of places, concepts and processes throughout
Well-integrated awareness of scale and change over time
Detailed, relevant analysis and evaluation throughout
A detailed conclusion that follows logically from the argument and applies knowledge to the question
Level 3 (11–15 marks)
Generally clear, accurate knowledge of places, concepts and processes
Generally clear awareness of scale and change over time
Generally clear, relevant analysis and evaluation
A clear conclusion based on knowledge applied to the question
Level 2 (6–10 marks)
Some relevant knowledge, which may include a few inaccuracies
Some partly relevant analysis and evaluation
Some sense of a conclusion, only partly based on the knowledge given
Some awareness of scale and change over time
Level 1 (1–5 marks)
Very limited knowledge and understanding
Very limited analysis and evaluation, which lacks clarity
A very limited or unsupported conclusion
Very limited awareness of scale and change over time
What separates Level 3 from Level 4?
Level 3 essays make clear points and reach a judgement, but the evidence or evaluation is not detailed all the way through
Level 4 essays keep one line of reasoning from start to finish
Each paragraph in a Level 4 essay uses named, specific evidence to move the argument forward
The conclusion then answers the exact question, using the argument already made
How to answer a 20-mark question
Step 1
Read the question carefully and highlight the command phrase
"With reference to a tropical rainforest that you have studied, assess the extent to which deforestation is the main threat to its carbon and water cycles."
"Assess the extent to which" means that you need to weigh the importance of deforestation against other threats and reach a judgement
Step 2
Highlight the key words
"With reference to a tropical rainforest that you have studied, assess the extent to which deforestation is the main threat to its carbon and water cycles."
In this example, your essay must:
use a named tropical rainforest
cover both the carbon cycle and the water cycle
compare deforestation with at least one other threat
Step 3
Spend about 3 minutes writing a short plan
Decide your judgement first, so that every paragraph can support it
A plan for this question could be:
opening position: deforestation is the main threat, but it's closely linked to climate change
argument 1: deforestation and the carbon cycle
argument 2: deforestation and the water cycle
counter-argument: climate change and drought
other threats: roads and mining as drivers of deforestation
link: the positive feedback loop and the tipping point
variation: scale and time differences across the forest and changes over time
conclusion: a judgement that returns to "main threat"
Step 4
Write your essay, opening with a clear position on the question
Give each paragraph one main idea that supports or challenges your position
Support each point with named, specific evidence:
General: “Deforestation has happened quickly in the Amazon”
Specific: “Brazil’s Legal Amazon had lost about 17–20% of its original forest by 2021”
Learn a few accurate figures for each case study, rather than trying to memorise many
Finish each paragraph by explaining what the evidence means for the question
Knowledge only: “Clearance and burning release carbon from biomass and soils. Pasture and soy store far less carbon than mature forest”
Knowledge and argument: “Clearance and burning release carbon from biomass and soils, and pasture and soy store far less. This strengthens the case for deforestation as the main threat, because carbon is released quickly but forest regrowth takes decades”
Consider scale and change over time wherever they help your argument
Finish with a judgement that draws together the points you have already made
What if?
You're running out of time: stop adding evidence and write a short judgement that answers the question, then move on so that your next essay gets its full share of time
You can't remember a figure: don't guess. Use a rounded figure you're sure of, such as "about a fifth", or a different accurate detail, because the top levels reward accurate knowledge
You've drifted from the question: don't start again. Add a sentence that links back to the key words, then use your remaining paragraphs and conclusion to answer the question set
Worked Example
With reference to a tropical rainforest that you have studied, assess the extent to which deforestation is the main threat to its carbon and water cycles.
[20 marks]
Model answer:
Deforestation is currently the main threat to the Amazon’s carbon and water cycles because it acts directly on both and weakens the forest’s resistance to other threats. [Ap] However, climate change also reaches uncleared forest, so the judgement depends on timescale and location. [Ap]
Clearance and burning transfer carbon from biomass, litter and soil to the atmosphere through combustion and decomposition. [KU] The Amazon’s trees and soils form one of the world’s largest land-based carbon stores, which built up over long periods. [KU] Pasture and soy store far less carbon than mature forest, so clearance reduces both the store and future uptake. [Ap] This makes clearance especially damaging, because carbon is released quickly but forest regrowth takes decades. [Ap]
Forest canopies intercept rain and return moisture through evapotranspiration, which supplies about 25–50% of Amazon rainfall. [KU] Clearance reduces these flows and increases surface runoff. [KU] Air crossing the basin recycles moisture several times, so clearance in one area can reduce rainfall further downwind. [Ap] This is the strongest evidence for deforestation because a local land-use change weakens the water cycle at a regional scale. [Ap]
Climate change is the main alternative. Droughts in 2005, 2010 and 2015–16 reduced water availability and killed trees. [KU] Long-term monitoring plots in the forest gained biomass more slowly in the 2000s than in the 1990s, partly because of climate variability and higher tree mortality. [KU] Climate change therefore affects both cycles without any clearance, and it is much harder to control. [Ap] However, those forest plots remained a net sink, and higher CO2 may boost growth, so climate change has so far acted more slowly than clearance. [Ap]
Roads and mining also threaten the forest, but mainly by enabling clearance, as most deforestation occurs close to roads or rivers. [KU] They are therefore drivers of deforestation more than rival threats, so they strengthen rather than weaken the case for deforestation. [Ap]
The threats also reinforce each other. Forest edges dry out and burn more easily, and fire dries surrounding forest, which raises fire risk the next year. [KU] Reduced evapotranspiration lowers rainfall, increasing drought stress and fire in a positive feedback loop. [KU] Scientists once suggested a tipping point of about 40% forest loss, but this falls to 20–25% once climate change and fire are included, and about 17–20% has been cleared. [KU] Climate change therefore lowers the threshold, but clearance moves the forest towards it. [Ap]
The threat varies over space and time. South-eastern Amazonia has become a net carbon source, linked to both deforestation and a stronger dry season, and emissions are higher in the east than the west. [KU] Deforestation therefore appears most damaging in the east, although climate is also a factor there. [Ap] Brazilian Amazon clearance fell by 84% between 2004 and 2012, then rose to a peak in 2021 before falling by 2024. [KU] This shows that policy can reduce it quickly, so its position as the main threat is not fixed. [Ap]
Overall, deforestation is the main threat at present because it removes carbon stores immediately, weakens rainfall recycling and increases vulnerability to drought and fire. [Ap] This judgement is strongest in the south-east and in the short term. [Ap] If clearance keeps falling, climate change could become the greater long-term threat because it is widespread and affects intact forest. [Ap]
[20 marks]
Mark allocation
This is a 'levelled response' question. Each valid point made in the answer does not equal a mark.
[KU] shows knowledge and understanding (AO1, 10 marks)
[Ap] shows application through analysis, evaluation and judgement (AO2, 10 marks)
Commentary
This answer reaches Level 4 because it keeps one line of reasoning throughout:
Paragraph 1: gives a clear position on "main threat" and shows what the judgement depends on
Paragraphs 2 and 3: build the case for deforestation, with one paragraph for each cycle
Paragraph 4: gives a counter-argument using climate change, then weighs it against clearance
Paragraph 5: considers other threats and explains why they mainly drive deforestation
Paragraph 6: links the threats through a complete feedback loop and a tipping point
Paragraph 7: shows awareness of scale and change over time
Paragraph 8: reaches a qualified judgement without adding new evidence
Common errors
Common errors that hold essays below the top level include:
describing the Amazon without linking the facts to "main threat"
writing about only one of the two cycles
listing other threats without weighing them against deforestation
describing part of a feedback loop without completing it
using a general rainforest rather than a named one
adding new evidence in the conclusion
Alternative content
The answer above is just one example of a response to this question. Other information that could be used in the answer includes:
A different named tropical rainforest, such as Borneo or the Congo Basin
Methane released from reservoirs that flood forest, such as Belo Monte in Brazil
Methane from cattle ranching on cleared land
Attempts to reduce deforestation, such as Brazil's Forest Code or the Amazon Fund
Examiner Tips and Tricks
Check which way the question runs before you plan. "The impact of the carbon budget on a rainforest" is a different question from "the impact of a rainforest on the carbon budget". If you do write about the other direction, complete the feedback loop so that it comes back to the question set.
Think of your conclusion as your final answer to the question, not a summary of everything you've written. Use it to draw your strongest points together, and save all your evidence for the paragraphs before it. Check your place knowledge too. Examiners have reported essays that put polar bears in Antarctica and rely on out-of-date stereotypes of places, so use details that are accurate and current.
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