A1.1 Water

A1.1.1 Water as the medium for life

A1.1.2 Hydrogen bonds as a consequence of the polar covalent bonds within water molecules

A1.1.3 Cohesion of water molecules due to hydrogen bonding and consequences for organisms

A1.1.4 Adhesion of water to materials that are polar or charged and impacts for organisms

A1.1.5 Solvent properties of water as a medium for metabolism and transport

A1.1.6 Physical properties of water and the consequences for animals in aquatic habitats

A1.1.7 Extraplanetary origin of water on Earth and reasons for its retention (HL only)

A1.1.8 Relationship between the search for extraterrestrial life and the presence of water (HL only)