IB Biology HL · 2025
Unit 4: Continuity and change
99 past paper questions from 8 papers across 2 exam sessions. See what repeats, then practise the same skills with AI marking.
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HL archive · 2025 to 2026
Unit 4: Continuity and change
Latest exam session: May 2026
- questions
- 99
- questions
- papers
- 8
- papers
- exam sessions
- 2
- exam sessions
- micro-topics
- 46
Topics in Unit 4: Continuity and change
In syllabus order. The ring is the share of the marks each one carries.
4.1
DNA replication
3% of marks6 of the 187 marks across the 8 Biology HL papers analysed (3%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 5 questions
4.2
Protein synthesis
7% of marks14 of the 187 marks across the 8 Biology HL papers analysed (7%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 8 questions
4.3
Mutations and gene editing
8% of marks15 of the 187 marks across the 8 Biology HL papers analysed (8%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 10 questions
4.4
Cell and nuclear division
15% of marks28 of the 187 marks across the 8 Biology HL papers analysed (15%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 11 questions
4.5
Gene expression
9% of marks17 of the 187 marks across the 8 Biology HL papers analysed (9%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 6 questions
4.6
Water potential
4% of marks7 of the 187 marks across the 8 Biology HL papers analysed (4%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 4 questions
4.7
Reproduction
7% of marks14 of the 187 marks across the 8 Biology HL papers analysed (7%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 8 questions
4.8
Inheritance
8% of marks15 of the 187 marks across the 8 Biology HL papers analysed (8%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 10 questions
4.9
Homeostasis
16% of marks30 of the 187 marks across the 8 Biology HL papers analysed (16%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 12 questions
4.10
Natural selection
10% of marks18 of the 187 marks across the 8 Biology HL papers analysed (10%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 11 questions
4.11
Stability and change
3% of marks6 of the 187 marks across the 8 Biology HL papers analysed (3%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 3 questions
4.12
Climate change
9% of marks17 of the 187 marks across the 8 Biology HL papers analysed (9%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 11 questions
Exam pattern
How often each micro-topic has been examined, year by year. Each label is explained under the grid.
Does it repeat?
Top 4 of 46 micro-topics for the next sitting. Numbers are questions per year.
fewermore
| Micro-topic | 2025 | 2026 |
|---|---|---|
| 4Variation: the raw material, 2025: 4 questions | 2Variation: the raw material, 2026: 2 questions | |
| 4What mutations are & their types, 2025: 4 questions | 1What mutations are & their types, 2026: 1 question | |
| 3Codominance, multiple alleles & incomplete dominance, 2025: 3 questions | 1Codominance, multiple alleles & incomplete dominance, 2026: 1 question | |
| 3Homeostasis & negative feedback, 2025: 3 questions | 1Homeostasis & negative feedback, 2026: 1 question |
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Questions on Unit 4: Continuity and change, by exam session
Which papers asked about Unit 4: Continuity and change, and which question numbers. Open a paper to see them highlighted.
May 2026
19 questions across 2 papers
May 2025
51 questions across 6 papers
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Frequently asked questions
Short answers about this page.
Which Biology HL exam sessions are covered for Unit 4: Continuity and change?
2 exam sessions from 2025 to 2026, the latest May 2026. Every Paper 1 and 2 in every timezone is read and classified in full, which gives 8 papers in this archive.
Which Unit 4: Continuity and change topic comes up most?
Variation: the raw material (4.10.1): in 63% of papers, last seen May 26 P1 TZA. Usually "identify", worth about 2 marks in a paper that includes it.
Can I see the original question and mark scheme?
No. The wording belongs to the IB. You get the citation, the marks, the command term and the skill tested, plus our own matched practice questions with worked answers and AI marking.
What do "banker", "due" and "rising" mean?
Banker: examined in at least one sitting in four and still appearing. Due: regular before, but absent for the last two exam sessions. Rising: clearly more common in the last two years. Our classification of real papers, not an IB statistic.
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