A - Unity and Diversity
B - Form and Function
C - Interaction and Interdependence
C1.1 Enzymes and metabolism
C1.2 Cell respiration
C1.3 Photosynthesis
C2.1 Chemical signalling (HL)
C2.2 Neural signalling
C3.1 Integration of body systems
C3.2 Defense against disease
C4.1 Populations and communities
C4.2 Transfer of energy and matter
D - Continuity and Change