AFOQT Practice Test

What are icebergs primarily made up of?

1. Salt water

2. Fresh water

3. Glacial ice

4. Ocean sediments

The correct answer is: Glacial ice

Icebergs are primarily made up of glacial ice. This glacial ice forms from the accumulation and compaction of snow over long periods of time in polar regions or high mountain areas. When this ice becomes dense enough, it begins to flow under its own weight, eventually breaking off from glaciers and entering the ocean, resulting in the formation of icebergs. The process of glacial formation includes the transformation of snow to firn and then to glacial ice, which is typically composed of fresh water, since the original snow that contributes to glacier formation consists of precipitation. While icebergs are indeed made of fresh water in the sense that they originate from freshwater sources, the defining characteristic that directly identifies icebergs is that they are formed from glacial ice. Other options, such as salt water and ocean sediments, do not accurately describe the primary composition of an iceberg, making glacial ice the most accurate answer.