BIOLOGY-YBI11 · Pearson Edexcel International A Level
BIOLOGY-YBI11/21
Paper 2
Biology · 2024 · Variant 1
Relative difficulty
Analysis source: Pearson Edexcel
Analysis aligned to the official syllabus and assessment design.
3.8 / 5
440
550 min
Data Evaluation, Experimental Design, and Statistical Analysis
Cohort performance
Session statistics from official examination reports
Total marks
440
Duration
550 min
Session difficulty
3.8 / 5
Key examiner messages
Top priorities from the principal examiner before you revise
A significant proportion of marks was lost on questions involving data interpretation and mathematical precision.
In Unit 1 (WBI11) and Unit 2 (WBI12), candidates frequently lost marks by failing to recognize the significance of overlapping standard deviation (SD) bars, which indicates that a difference is not statistically significant.
Additionally, in Unit 5 (WBI15) and Unit 4 (WBI14), many struggled to accurately articulate the distinction between DNA methylation and histone modification, or failed to connect T-helper cell depletion with a weakened humoral response.
Question difficulty map
How candidates performed on each question in this series
No data available in official reports
Assessment objectives
Skill and AO weighting from official examiner commentary
Skill weighting
Shows the skill mix this paper tested most heavily.
Biological
Weight: 5100%Recall
Weight: 480%Experimental
Weight: 360%Mathematical and
Weight: 240%Analysis and
Weight: 120%
Method marks watchlist
Where working, steps, or method marks were commonly lost
No data available in official reports
Recurring mistakes across years
Themes examiners flag in multiple recent sessions for this subject
No data available in official reports
Question choice intelligence
Mean scores and popularity for optional questions (HKDSE electives)
No data available in official reports
Level exemplars
What candidate scripts at each grade level looked like
No data available in official reports
Grade & admission context
How marks relate to grade thresholds and entry standards
Report type
Examiner report — national grade boundaries and question-level commentary
Level A*
Approx. 90% of maximum mark
Level A
Approx. 80% of maximum mark
Level B
Approx. 70% of maximum mark
Level C
Approx. 60% of maximum mark
Level D
Approx. 50% of maximum mark
Level E
Approx. 40% of maximum mark
Deep insights
What top candidates did
Techniques and approaches examiners rewarded in this series
No data available in official reports
Command word playbook
How to match each command word to the expected response style
Give reasons and link mechanism to outcome; each point needs a because/so chain.
State features in sequence or list observable properties — do not explain causes unless asked.
Show formula, substitution, and unit; method marks need visible working.
Apply knowledge to an unfamiliar context; concise, practical points score best.
Weigh arguments for and against with evidence; end with a supported judgement.
Match the expected response style for “Deduce” questions.
Match the expected response style for “Devise” questions.
Match the expected response style for “State” questions.
Time traps
Sections where candidates spent disproportionate time relative to marks
Min per mark: 1.6
Min per mark: 1.2
Min per mark: 1.1
Syllabus traceability
Topics linked to questions and mark weighting in this session
Molecules, Transport and Health
70 marks this session
Membranes, Proteins, DNA and Gene Expression
65 marks this session
Plant Structure and Function, Biodiversity and Conservation
65 marks this session
MCQ trap analytics
Commonly chosen wrong options from examiner commentary
No data available in official reports
Topic heatmap across years
Mark concentration by topic and exam year for this subject
Mark intensity
Plant Structure and Function, Biodiversity and Conservation
Coordination, Response and Gene Technology
Membranes, Proteins, DNA and Gene Expression
Respiration, Muscles and the Internal Environment
Microbiology, Immunity and Forensics
Molecules, Transport and Health
Energy Flow, Ecosystems and the Environment
Paper comparison
Marks and duration breakdown across papers in this session
WBI11/01: Unit 1 - Molecules, Diet, Transport and Health: WBI12/01: Unit 2 - Cells, Development, Biodiversity and Conservation: WBI13/01: Unit 3 - Practical Skills in Biology I: WBI14/01: Unit 4 - Energy, Environment, Microbiology and Immunity: WBI15/01: Unit 5 - Respiration, Internal Environment, Coordination and Gene Technology: WBI16/01: Unit 6 - Practical Biology and Investigative Skills:
Marks you can still earn
Where valid approaches outside the mark scheme may still gain credit
No data available in official reports
Practise what examiners flagged
Target weak topics from this report inside the Revui app
Molecules, Transport and Health
70 marks this session
Practise in RevuiMembranes, Proteins, DNA and Gene Expression
65 marks this session
Practise in RevuiPlant Structure and Function, Biodiversity and Conservation
65 marks this session
Practise in RevuiSelf-diagnostic checklist
Key actions before you sit this paper — copy and tick off as you revise
- 1Message
A significant proportion of marks was lost on questions involving data interpretation and mathematical precision.
- 2Message
In Unit 1 (WBI11) and Unit 2 (WBI12), candidates frequently lost marks by failing to recognize the significance of overlapping standard deviation (SD) bars, which indicates that a difference is not statistically significant.
- 3Message
Additionally, in Unit 5 (WBI15) and Unit 4 (WBI14), many struggled to accurately articulate the distinction between DNA methylation and histone modification, or failed to connect T-helper cell depletion with a weakened humoral response.
Teacher briefing pack
One-page session summary for tutors and classroom review
2024 2024
Biology
A significant proportion of marks was lost on questions involving data interpretation and mathematical precision. In Unit 1 (WBI11) and Unit 2 (WBI12), candidates frequently lost marks by failing to recognize the significance of overlapping standard deviation (SD) bars, which ind
A significant proportion of marks was lost on questions involving data interpretation and mathematical precision.
In Unit 1 (WBI11) and Unit 2 (WBI12), candidates frequently lost marks by failing to recognize the significance of overlapping standard deviation (SD) bars, which indicates that a difference is not statistically significant.
Additionally, in Unit 5 (WBI15) and Unit 4 (WBI14), many struggled to accurately articulate the distinction between DNA methylation and histone modification, or failed to connect T-helper cell depletion with a weakened humoral response.
- Total marks
- 440
- Duration
- 550 min
- Session difficulty
- 3.8 / 5
Session analysis
A significant proportion of marks was lost on questions involving data interpretation and mathematical precision. In Unit 1 (WBI11) and Unit 2 (WBI12), candidates frequently lost marks by failing to recognize the significance of overlapping standard deviation (SD) bars, which indicates that a difference is not statistically significant. Additionally, in Unit 5 (WBI15) and Unit 4 (WBI14), many struggled to accurately articulate the distinction between DNA methylation and histone modification, or failed to connect T-helper cell depletion with a weakened humoral response.
Updated Jun 12, 2026
Paper breakdown
WBI11/01: Unit 1 - Molecules, Diet, Transport and Health: WBI12/01: Unit 2 - Cells, Development, Biodiversity and Conservation: WBI13/01: Unit 3 - Practical Skills in Biology I: WBI14/01: Unit 4 - Energy, Environment, Microbiology and Immunity: WBI15/01: Unit 5 - Respiration, Internal Environment, Coordination and Gene Technology: WBI16/01: Unit 6 - Practical Biology and Investigative Skills:
Top chapters
Exam structure insights
Marks by chapter
See where the marks were concentrated so revision time goes to the highest-value topics.
Mark accessibility
Estimate which marks were basic, mid-level, or high-difficulty.
77% within easy or medium reach
Command word frequency
Spot common command words so answers match the expected response style.
Question type mix
Compare the mark share of each paper section and question type.
Short Answer / Structuring Answers
210·85·48%
Extended Open Response / Devise / Evaluation
(Level of Response)
110·18·25%
Graph Sketching / Plotting
50·10·11%
Calculations and Standard Form
40·22·9%
Multiple Choice Questions
(MCQs)
30·30·7%
Study ROI
Bigger bubbles recur more often; higher bubbles carry more marks, helping you rank revision priorities.
Difficulty trend
Compare difficulty across recent years.
Time vs marks
Compare marks with suggested time allocation to plan exam pacing.
IAS Unit 1 & 2 Core
0.89 m/minIAS & IA2 Practical
0.63 m/minIA2 Unit 4 & 5 Core
0.86 m/minTotal marks
440
Total time
550 min
Avg pace
0.80
Next-year prediction
Topics worth watching next year, with the reason shown directly below each bar.
Antibiotic Resistance, Selection Pressures and Natural Selection
95%95%
Fluid Mosaic Model & Temperature Effects on Membrane Permeability
90%90%
Genetic Crosses, Sex Linkage and Pedigree Diagrams
85%85%
Analysis is paraphrased for study purposes. Always verify against the official examiner report and mark scheme.