C3.2 Defence against disease

Defence against disease combines physical barriers, clotting, phagocytes, lymphocyte specificity, vaccination, antibiotics and evolutionary responses to pathogens across human populations.

What you’ll learn

18 learning objectives

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

Exam analysis

An aggregate view of how the complete C3.2 Defence against disease appears across past papers.

Chance of appearing44%of analysed past papers

Latest appearanceNovember 2025

Most common paperPaper1

Most tested objectives

C3.2.14—Antibiotic resistance evolution19 questions
C3.2.13—Antibiotics11 questions
C3.2.3—Blood clotting10 questions

Common question formats

Structured response
Definition or recall
Data analysis
Evaluation
Process explanation
Diagram interpretation
Extended response
Calculation

Exam question appearances

November 2025Paper1A ["SL"] · TZ118[ 1 ]C3.2.15—Zoonoses

November 2025Paper1A ["SL"] · TZ117[ 1 ]C3.2.6—Lymphocytes

May 2025Paper1B ["SL"] · TZ33(b)(ii)[ 1 ]C3.2.16—Vaccines and immunization

May 2025Paper1B ["SL"] · TZ33(b)(i)[ 1 ]C3.2.16—Vaccines and immunization

May 2025Paper1A ["SL"] · TZ319[ 1 ]C3.2.15—Zoonoses

Coverage 2010–2025 · Updated 16 Jul 2026