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C4.2.22—Recycling of all chemical elements

Recycling of all chemical elements explains how energy flow, matter cycling or carbon transfer is represented, measured or limited within ecosystems.

Syllabus
First assessment 2025
Objective
C4.2.22
Level
SL

Exam analysis

Chance of appearing2%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1
Typical marks1–7

Common command terms

  • Identify
  • Describe
  • Outline
  • Explain
  • Suggest

Scoring notes

Common mistake
Confusing detritivores that ingest material with saprotrophs that digest externally.

Recent exam appearances

May 2025Paper2 ["SL"] · TZ38(c)[ 7 ]C4.2.22—Recycling of all chemical elements
November 2023Paper3 ["SL"] · TZ111(c)[ 2 ]C4.2.22—Recycling of all chemical elements
May 2012Paper1 ["SL"] · TZ119[ 1 ]C4.2.22—Recycling of all chemical elements
Practice this objective

Coverage 2012–2025 · Updated 16 Jul 2026

Concept essentials

  • Recycling of all chemical elements must be linked to the correct source, store, transfer or loss process.
  • The evidence for recycling of all chemical elements depends on distinguishing energy flow from matter cycling.
  • Recycling of all chemical elements is clearer when arrows, units and trophic positions match the biological process.
  • Data or diagrams for recycling of all chemical elements need interpretation as ecosystem transfer evidence.
ConceptIB Biology SL