Which of these substances is usually not present in explosive volcanic eruptions? . a) pahoehoe. b) aa. c) volcanic bombs. d) cinders. e)volcanic ash.

The substance that is usually not present in explosive volcanic eruptions is : A Pahoehoe

Pahoehoe is the one that causes the explosion within the volcanoe , not the substance that present as the result of the eruption

The answer to this question is  c. pharmaceutical accumulation  reclaimed water refers to the water that being used again after it already  used for agricultural purposes.this type of water often contains pharmaceutical accumulation because of the chemical fertilizer that is used for the plants is absorbed into the water.