20. Low-lying river floodplains, tide flats and artificially-filled areas face a common hazard during earthquakes, as they (a) Tend to amplify earthquake waves passing through them
(b) Are prone to liquefaction, and lose their load-bearing capacity
(c) Build standing waves which fracture the ground
(d) Rapidly subside (sink) as water drains due to shaking

21. Longshore drift describes the movement of sand on beaches. This movement is driven by

(a) Ocean currents
(b) Coastal winds
(c) Ocean waves
(d) Sediment pressures

22. Waves get higher as they approach the shoreline. This happens as the wave

(a) slows down as the water depth decreases
(b) runs into water draining back into the ocean
(c) speeds up as the water depth gets shallower
(d) combines with other waves

23. There are a wide range of things that you can do to prepare for an earthquake. The minimal first step is to:

(a) Wear a helmet when earthquakes are forecast
(b) Turn off the gas, water and power
(c) Stockpile batteries and ammunition
(d) Hide an old pair of shoes under your bed
(e) Recognize the profit potential of such events.

24. Each igneous rock comes in two varieties- plutonic and volcanic. The difference between these two varieties is

(a) their chemistry, depending on how far they rose through the crust.
(d) their mineral composition, depending on where they crystallized
(c) their atomic structure, depending on how deep they cooled
(e) their crystal size, depending on how long they cooled