Evaluate advantages and disadvantages of GM crops
Genetically modified crops can improve yield, resistance or nutrition, but evaluation should consider environmental, ecological and social trade-offs.
Section 21.3 · Genetic modification
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
- Know that genes are sections of DNA and that organisms use enzymes in cellular processes.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Which is a possible intended benefit of a GM crop listed in the syllabus?
What you will learn
- Discuss possible advantages and disadvantages of genetically modified soya, maize and rice
- Use evidence and context to evaluate a crop modification
Evaluate the intended benefit
A modified crop may resist insect pests or herbicides, or have improved nutritional qualities. These traits may reduce crop damage, change weed control, increase usable yield or address a nutrient deficiency, depending on the trait and growing conditions.
For example, an insect-resistant crop may reduce losses from a target pest. A herbicide-resistant crop may allow a farmer to control weeds without damaging the crop. Improved nutrition may increase a desired nutrient in the edible part.
Weigh risks and context
Possible disadvantages include unintended effects on non-target organisms, gene flow to related plants, development of resistant pests or weeds, reduced crop diversity if one variety dominates, and cost or access concerns. Whether a risk occurs depends on the crop, trait, ecosystem and management.
A balanced evaluation compares a stated benefit with relevant risks and evidence. Do not claim that every genetically modified crop has the same effect, or that genetic modification automatically makes food unsafe or harmless.
Pause and explain
A trial measures target-pest damage but not other insects. What is a valid evaluation?
Worked example
A maize variety resists a pest and reduces crop damage in a trial, but nearby non-target insects were not measured. Give one supported benefit and one uncertainty.
Show the worked solution
- Use the measured crop-damage result.
- Identify the unmeasured non-target effect.
Answer The trial supports reduced crop damage from the target pest. It does not show what happens to nearby non-target insects, so that ecological effect remains uncertain.
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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.
Give two possible advantages and two possible disadvantages to consider when evaluating a GM crop.
Give me a hint
Balance intended crop traits with ecological or access concerns.
Compare my reasoning
- Possible advantages include pest resistance and improved nutritional quality.
- Possible disadvantages include non-target effects, gene flow, resistance or cost/access concerns.
Possible advantages include resistance to target pests or herbicides and improved nutritional quality. Possible disadvantages include effects on non-target organisms, gene flow, resistant pests or weeds, reduced diversity and cost/access concerns; relevance depends on the crop and setting.
Look for these in your work
- Two advantages included
- Two disadvantages included
A GM rice trial has higher measured nutrient content but uses one location and one growing season. State a supported conclusion and one limitation.
Give me a hint
Match the conclusion to the measured nutrient and trial scope.
Compare my reasoning
- The tested rice had higher nutrient content under the trial conditions.
- One location and season may not represent every environment or year.
The trial supports that the modified rice had higher measured nutrient content under the tested conditions. One site and season do not establish the same result for all environments or years.
Look for these in your work
- Evidence-based conclusion
- Scope limitation identified
A farmer considers an herbicide-resistant crop. Explain one possible benefit and one concern that should be assessed.
Give me a hint
Consider weed control and resistance or gene flow.
Compare my reasoning
- The crop may tolerate a particular herbicide, allowing weeds to be controlled.
- Repeated use may select resistant weeds; gene flow can also be assessed where related plants grow.
A herbicide-resistant crop may allow the farmer to control weeds without harming the crop. Repeated herbicide use could select resistant weeds, and potential gene flow to related plants should be considered for the local setting.
Look for these in your work
- Benefit linked to trait
- Concern tied to context
Common mistakes
- Treating all GM crops as having identical risks or benefits
- Claiming a trial proves effects beyond the crop and conditions tested
- Ignoring possible non-target and resistance effects
What can you explain now?
Which is a possible intended benefit of a GM crop listed in the syllabus?
Compare with the explanation
Improved nutritional quality
This is one of the listed crop traits.
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Make it stick
How can you evaluate GM crops by weighing intended crop benefits against ecological, resistance and access considerations?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.