Compare crop-establishment data and weigh both population contexts
Calculate success fractions and give a conditional wild-and-crop discussion.
Exam scope and assessment notes
Extended only (Supplement) · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall cells, DNA, inherited characteristics and the distinction between growth of an organism and production of offspring.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is the difference between 75% and 60%?
What you will learn
- Keep establishment percentages separate from genotype and yield
- Use advantages and disadvantages in both required contexts
Compare crop-establishment data and weigh both population contexts
Invented nursery outcome: 30/40 cuttings = 75%; 24/40 seedlings = 60%. Difference 15 percentage points; relative increase from 60% is 25%. Establishment is not final yield or a genotype test. Original teaching model.
| Group | Starting total | Established |
|---|---|---|
| Cuttings | 40 | 30 |
| Seedlings | 40 | 24 |
| Feature | Meaning |
|---|---|
| Cuttings | 30 established; 10 not yet established |
| Seedlings | 24 established; 16 not yet established |
| Comparisons | 15 percentage points; 25% relative increase |
| Discussion | Separate wild-population and crop benefits and risks |
Keep establishment percentages separate from genotype and yield
An invented nursery comparison starts with 40 cuttings and 40 seedlings under its stated conditions. At the same observation time, 30 cuttings and 24 seedlings meet the defined establishment criterion of roots and a new shoot. The success percentages are 30/40 × 100 = 75% and 24/40 × 100 = 60%. The cutting group is 15 percentage points higher in this record.
The relative increase from the seedling group’s 60% is 15/60 × 100 = 25%, which is different from a 15-percentage-point difference. State which comparison is asked for. The 10 non-established cuttings and 16 non-established seedlings are not automatically dead; the criterion and observation time only establish whether each has met the supplied outcome.
Use advantages and disadvantages in both required contexts
This comparison measures establishment, not identical genotype, disease freedom, final yield or the best method for every crop. The copying history supplies expected genotype retention for the cuttings; the counts do not prove it. Repeated comparisons, comparable stock and control of environmental differences would be needed for broader performance conclusions. A single invented record is not universal experimental proof.
A complete discussion addresses both syllabus contexts. In the wild, no mate requirement and retaining a suitable genotype can help establishment, while limited lineage diversity and some local competition create risks. In crops, retaining selected inherited traits and predictable crop type can help production, while shared susceptibility, infected donor material and establishment costs matter. The final judgment depends on the stated goal and conditions rather than one numerical success fraction alone.
Pause and explain
What does this record directly measure?
Worked example
Calculate establishment percentages from 30/40 cuttings and 24/40 seedlings.
Show the worked solution
- 30/40×100 = 75%.
- 24/40×100 = 60%; subtract.
Answer Cuttings 75%; seedlings 60%; difference 15 percentage points.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Calculate establishment percentages and the percentage-point difference.
Give me a hint
Use each original group of 40.
Compare my reasoning
- 30/40 = 75%.
- 24/40 = 60%; 75−60 = 15.
Cuttings 75%; seedlings 60%; difference 15 percentage points.
Look for these in your work
- Use original denominators
- State percentage points
Find the relative increase from the seedling establishment percentage and the non-established counts.
Give me a hint
Use 60% as relative baseline; subtract counts from 40.
Compare my reasoning
- 15/60×100 = 25%.
- 40−30 = 10; 40−24 = 16.
Relative increase 25%; non-established cuttings 10 and seedlings 16. These counts do not establish that those plants are dead.
Look for these in your work
- Use relative baseline
- Do not infer death from an unmet criterion
Discuss one advantage and one disadvantage in the wild and in crop production, then qualify the nursery result.
Give me a hint
Address both contexts and match the claim to measured establishment.
Compare my reasoning
- Wild: no mate or suitable trait retention versus shared risk or crowding.
- Crops: selected-genotype retention versus shared susceptibility or infected material.
Wild populations can reproduce without a mate but a uniform lineage can share vulnerability. Crops can retain selected traits but share susceptibility or carry donor infection. The nursery record measures establishment only and does not prove universal superiority, identical yield or disease freedom.
Look for these in your work
- Address both contexts
- Give a conditional data conclusion
Common mistakes
- Calling 15 percentage points a 15% relative increase.
- Equating non-established with dead without evidence.
What can you explain now?
What does this record directly measure?
Compare with the explanation
Establishment by a defined observation time
It does not directly measure final yield or genotype.
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Make it stick
Calculate absolute and relative percentage comparisons, then discuss benefits and risks in both required contexts.
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