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C1.3.8—CO₂ enrichment experiments

Carbon dioxide enrichment experiments test whether elevated atmospheric carbon dioxide changes photosynthesis or growth under realistic environmental conditions, connecting the mechanism to observable photosynthesis evidence.

Syllabus
First assessment 2025
Objective
C1.3.8
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1A
Typical marks1

Common command terms

  • Discuss

Recent exam appearances

May 2025Paper1A ["HL"] · TZ38[ 1 ]C1.3.8—CO₂ enrichment experiments
Practice this objective

Coverage 2025–2025 · Updated 15 Jul 2026

Concept essentials

  • FACE experiments expose plants to elevated carbon dioxide under more realistic field conditions.
  • Higher carbon dioxide does not always cause a higher growth rate.
  • Temperature and other limiting factors can alter enrichment responses.
  • Carbon dioxide enrichment data must be interpreted from the experimental graph or design.
ConceptIB Biology HL