Fill in the Blanks (Reading & Writing)

Salt production along shallow coastal flats relies on evaporation ponds that —concentrateconcentrationconcentratedconcentrating seawater over several weeks until only crystals remain. Workers rake the resulting —residueresidualresideresident into mounds before it is washed, dried and graded for sale. Because output depends entirely on sunshine and wind, a single rainy season can —ruinruinedruiningruins an entire year's harvest, leaving producers financially —exposedexposeexposingexposure.