Ground water

water that flows through naturally porous or fractured rocks and soils beneath the surface of the land; also, water trapped between dikes (vertical, underground sheets of volcanic rock) or floating on seawater within rocks (C3, R1)


somewhat salty, but not as salty as ocean water (C2, C3)

Anchialine pond

a brackish or saltwater pool with no surface connection to the ocean (C3)


a change in an organism or species that enables it to survive in a particular habitat (A3, C3, R3, M2, M3)