a large colony of ants in which it is often impossible to distinguish between individual nests (A4)


single-celled organisms that live in the tissue of corals and provide energy to the corals (M2)


the distribution of plants and animals according to environmental conditions, generally in a pattern of vertical banding (M3)


in traditional Polynesian voyaging, the person who navigates the canoe using no instruments (M1)

Water budget

a model that estimates how much water enters and leaves a particular area, and through which mechanisms (R1)


a place where magma (molten rock) and/or gas comes to the surface from within the earth’s core (A1)

Volcanic ejecta

fragments of lava or already solidified rock that is thrown into the air (or ‘ejected’) by a volcanic explosion (A1)

Volcanic ash

volcanic ejecta that is less than .5 centimeters (.2 inch) in diameter comprised of already solid rock, crystals from solid rock, or particles of lava that were thrown up as liquid spray (A1)