A - Unity and Diversity
A1.1 Water
A1.2 Nucleic acids
A2.1 Origins of cells (HL)
A2.2 Cell structure
A2.3 Viruses (HL)
A3.1 Diversity of organisms
A3.2 Classification and cladistics (HL)
A4.1 Evolution and speciation
A4.2 Conservation of biodiversity
B - Form and Function
C - Interaction and Interdependence
D - Continuity and Change