EduNinja

C3.1 Integration of body systems

Integrated body systems coordinate neural, hormonal and plant responses through receptors, control centres and effectors, maintaining function across organisms and changing environmental conditions.

Syllabus
First assessment 2025
Topic
C3.1
Level
—

What you’ll learn

23 learning objectives

Choose one objective for a focused lesson, or study the complete topic.

Exam analysis

An aggregate view of how the complete C3.1 Integration of body systems appears across past papers.

Chance of appearing45%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper3

Most tested objectives

  1. C3.1.9—Pain reflex arcs24 questions
  2. C3.1.4—Brain as information integration organ23 questions
  3. C3.1.14—Heart rate feedback control20 questions

Common question formats

  • Structured response
  • Definition or recall
  • Diagram interpretation
  • Process explanation
  • Extended response
  • Calculation
  • Experimental design
  • Comparison
  • Data analysis
  • Graph interpretation

Exam question appearances

November 2025Paper2 ["HL"] · TZ34(b)(ii)[ 2 ]C3.1.19 (HL)—Phytohormones
November 2025Paper1A ["HL"] · TZ328[ 1 ]C3.1.9—Pain reflex arcs
November 2025Paper1A ["HL"] · TZ327[ 1 ]C3.1.11—Melatonin and sleep
November 2025Paper1A ["HL"] · TZ127[ 1 ]C3.1.20 (HL)—Auxin efflux carriers
November 2025Paper1A ["HL"] · TZ126[ 1 ]C3.1.9—Pain reflex arcs
Practice this topic

14 original exam-style questions based on the patterns above.

Coverage 2010–2025 · Updated 16 Jul 2026

Study checklistC3.1 Integration of body systems