WACE Biology most tested topics
Across the six SCSA Biology external papers from 2020 to 2025, Continuity of life on Earth carries 21.8% of the marks against 1.0% for Science as a Human Endeavour (Unit 4), so the paper rewards Continuity of life on Earth more than any other topic. At dot-point level 4.3.2 carries 7.0% of paper marks, and four of the 61 dot points that the board assesses externally have not appeared in one of these papers. Every percentage below covers the 99.7% of marks that map to a syllabus dot point.
Computed from 6 SCSA Biology external papers, 2020 to 2025: 234 questions, 452 question parts and 1260 marks.
Unit, topic and dot-point shares below are of the 1256 marks that map to a dot point, so each of those tables adds to 100%. 107 of the 452 parts are assessed against more than one dot point, and their 487 marks are divided evenly between the dot points they cover.
What these papers are
| Year | Exam | Questions | Marks |
|---|---|---|---|
| 2025 | Exam | 39 | 210 |
| 2024 | Exam | 39 | 210 |
| 2023 | Exam | 39 | 210 |
| 2022 | Exam | 39 | 210 |
| 2021 | Exam | 39 | 210 |
| 2020 | Exam | 39 | 210 |
Marks by unit
| Unit | Share of marks |
|---|---|
| Unit 3: Continuity of species | 52.0% |
| Unit 4: Surviving in a changing environment | 48.0% |
Marks by topic
| Topic | Share of marks | Papers it appears in | Years |
|---|---|---|---|
| Continuity of life on Earth | 21.8% | 6 of 6 | 6 of 6 |
| Heredity | 21.7% | 6 of 6 | 6 of 6 |
| Homeostasis | 21.5% | 6 of 6 | 6 of 6 |
| Infectious disease | 19.5% | 6 of 6 | 6 of 6 |
| Science Inquiry Skills (Unit 4) | 6.0% | 6 of 6 | 6 of 6 |
| Science as a Human Endeavour (Unit 3) | 4.7% | 6 of 6 | 6 of 6 |
| Science Inquiry Skills (Unit 3) | 3.9% | 6 of 6 | 6 of 6 |
| Science as a Human Endeavour (Unit 4) | 1.0% | 6 of 6 | 6 of 6 |
Marks by dot point
Dot-point numbers and wording are SCSA's own. Where a dot point is written as a list, its items run together here separated by semicolons.
| Dot point | Content | Topic | Share of marks | Papers |
|---|---|---|---|---|
| 4.3.2 | thermoregulatory mechanisms include structural features, behavioural responses and physiological mechanisms to control heat exchange and metabolic activity; animals can be endothermic or ectothermic | Homeostasis | 7.0% | 6 of 6 |
| 4.4.4 | diseases caused by these major pathogen groups include tuberculosis, crown gall of plants; chytridiomycosis (amphibian chytrid fungus disease); malaria, Phytophthora dieback (jarrah dieback)*; influenza, Ross River virus, viral diseases of honeybees | Infectious disease | 5.1% | 6 of 6 |
| 4.4.10 | management strategies are used to control the spread of infectious diseases, including quarantine; immunisation – herd immunity; disruption of pathogen life cycle (including antibiotics and antivirals); physical preventative measures | Infectious disease | 5.1% | 6 of 6 |
| 4.3.4 | animals have a variety of behavioural, physiological and structural adaptations to maintain water and salt balance in terrestrial and aquatic environments | Homeostasis | 5.0% | 6 of 6 |
| 4.3.5 | to maintain water balance and allow for gas exchange, xerophytes and halophytes have a variety of structural and physiological adaptations | Homeostasis | 4.8% | 6 of 6 |
| 3.4.6 | gene pools are dynamic, with changes in allele frequency caused by mutations; differing selection pressures; random genetic drift, including the founder effect; changes in gene flow between adjoining groups | Continuity of life on Earth | 4.1% | 6 of 6 |
| 3.4.2 | evidence for the theory of evolution includes comparative genomics (molecular evidence); comparative studies of proteins (amino acid sequences); the fossil record; comparative anatomy and embryology | Continuity of life on Earth | 4.1% | 6 of 6 |
| 4.1.4 | represent data in meaningful and useful ways, including the use of mean, median, range and probability; organise and analyse data to identify trends, patterns and relationships; discuss the ways in which measurement error, instrumental accuracy, the nature of the procedure and sample size may influence limitations in data; and select, synthesise and use evidence to make and justify conclusions | Science Inquiry Skills (Unit 4) | 3.7% | 6 of 6 |
| 3.3.10 | frequencies of genotypes and phenotypes of offspring can be predicted using Punnett squares and are determined by patterns of inheritance, including dominance (dominant/recessive, co-dominance, incomplete dominance), autosomal and sex-linked alleles, multiple alleles and polygenes | Heredity | 3.2% | 6 of 6 |
| 4.4.5 | the life cycle of a pathogen and its associated diseases, including the method of invading the host, the impact on the host, and the mode of transmission, determines its success for survival | Infectious disease | 3.1% | 6 of 6 |
| 4.4.3 | the major groups of organisms that cause disease are bacteria, fungi, protists and viruses; each group can be distinguished by its structural characteristics | Infectious disease | 2.9% | 6 of 6 |
| 3.3.5 | protein synthesis involves transcription of a gene into messenger RNA in the nucleus, and translation into an amino acid sequence at the ribosome | Heredity | 2.9% | 6 of 6 |
| 3.3.3 | the structural properties of the DNA molecule, including nucleotide composition and pairing and the hydrogen bonds between strands of DNA, allow for replication | Heredity | 2.7% | 6 of 6 |
| 3.3.1 | continuity of life requires the replication of genetic material and its transfer to the next generation through processes, including binary fission, mitosis, meiosis and fertilisation | Heredity | 2.6% | 6 of 6 |
| 4.3.3 | the type of nitrogenous waste produced by different vertebrate groups can be related to the availability of water in the environment | Homeostasis | 2.6% | 6 of 6 |
| 3.1.4 | represent data in meaningful and useful ways, including the use of mean, median, range and probability; organise and analyse data to identify trends, patterns and relationships; discuss the ways in which measurement error, instrumental accuracy, the nature of the procedure and the sample size may influence limitations in data; and select, synthesise and use evidence to make and justify conclusions | Science Inquiry Skills (Unit 3) | 2.5% | 5 of 6 |
These 16 dot points carry 61.4% of the paper marks between them. Another 41 assessed dot points share the rest, and 4 of the 61 externally assessable dot points have not been assessed in any of these 6 papers. Content that has not appeared is still examinable.
What has moved between papers
No topic's share moved by more than 3.0 percentage points between the 2020 to 2022 papers and the 2023 to 2025 papers. The largest movement was 2.4 points, which is inside the range two papers a year produce by chance, so nothing here is a trend to revise around.
How the papers are built
Short answer carries 54.0% of the marks across these 6 papers.
| Question type | Share of marks | Marks | Parts |
|---|---|---|---|
| Short answer | 54.0% | 680 | 232 |
| Extended response | 31.7% | 400 | 40 |
| Multiple choice | 14.3% | 180 | 180 |
| Verb | Share of marks | Marks | Parts |
|---|---|---|---|
| explain | 37.3% | 470 | 74 |
| describe | 13.5% | 170 | 25 |
| outline | 7.6% | 96 | 30 |
| discuss | 7.1% | 90 | 9 |
| state | 7.0% | 88 | 43 |
| justify | 3.7% | 47 | 17 |
| list | 3.5% | 44 | 16 |
| identify | 2.5% | 32 | 15 |
What these percentages do not tell you
Where to practise
Every topic above links to its own page of real SCSA questions with marking criteria and average scores attached: Continuity of life on Earth, Heredity, Homeostasis, Infectious disease, Science Inquiry Skills (Unit 4), Science as a Human Endeavour (Unit 3), Science Inquiry Skills (Unit 3) and Science as a Human Endeavour (Unit 4). For how students actually score on this content, read WACE Biology hardest topics, and for the full question bank start at WACE Biology.
Frequently asked questions
Which topic carries the most marks in the WACE Biology external exam?
Continuity of life on Earth carries 21.8% of the marks across the 6 SCSA papers from 2020 to 2025, ahead of Heredity on 21.7%.
How are marks split between question types in the WACE Biology exam?
Short answer carries 54.0% of the marks, extended response carries 31.7% of the marks and multiple choice carries 14.3% of the marks, measured across 6 papers and 1260 marks from 2020 to 2025.
Has the topic balance changed in recent WACE Biology papers?
No. Comparing the 2020 to 2022 papers with the 2023 to 2025 papers, the largest movement in any topic's share was 2.4 percentage points, which is too small to plan revision around.
How many past papers is this WACE Biology analysis based on?
6 SCSA external papers from 2020 to 2025, covering 234 questions and 1260 marks. 0.3% of those marks carry no dot-point mapping and sit outside the percentages.
Sources
- ATAR Biology Course Examination, SCSA, 2025. 6 papers, 2020 to 2025, covering 234 questions and 1260 marks. Listed individually in the table at the top of this guide. Dot-point numbering follows the current SCSA Biology syllabus.
Syllabus and assessment material referenced in this guide is used under licence, © School Curriculum and Standards Authority. See our SCSA licensing notice. The School Curriculum and Standards Authority does not endorse this publication or product.
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