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C4.2.19—CO₂ release during combustion

CO₂ release during combustion explains how energy flow, matter cycling, trophic transfer or carbon movement is represented, measured or limited within ecosystems.

Syllabus
First assessment 2025
Objective
C4.2.19
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceMay 2019
Most common paperPaper3
Typical marks1–2

Common command terms

  • Calculate
  • Compare
  • Contrast
  • Identify
  • State

Scoring notes

Common mistake
Reversing photosynthesis and respiration arrows in carbon-cycle diagrams.

Recent exam appearances

May 2019Paper3 ["HL"] · TZ23(b)[ 2 ]C4.2.19—CO₂ release during combustion
May 2019Paper3 ["HL"] · TZ23(a)[ 1 ]C4.2.19—CO₂ release during combustion
Practice this objective

Coverage 2019–2019 · Updated 16 Jul 2026

Concept essentials

  • CO₂ release during combustion must be linked to the correct source, store, transfer or loss process.
  • The evidence for co₂ release during combustion depends on distinguishing energy flow from matter cycling.
  • CO₂ release during combustion is clearer when arrows, units and trophic positions match the biological process.
  • Data or diagrams for co₂ release during combustion need interpretation as ecosystem transfer evidence.
ConceptIB Biology HL