Answer:
A) They prevent high water from pouring into towns, and can hold excess water in storage compartments.
Explanation:
Flood barriers are called "Flood barriers", for they form a "barrier", or a control against a problem, or "floods". The definition of a flood is the pouring out of large amounts of water over what was previously land, and causes destruction to habitat or infrastructure in the area. Flood barriers make sure that these floodings near infrastructures is impeded.
However, you must note that flood barriers can also be detrimental to marine life and farming. Flood generally can bring marine life into rivers and such, which would, when blocked off, not only affect fishing industries, but also how the fishes reproduce. Farming can also be affected, because flooding generally leave silt, a high-nutrient soil perfect for farming.
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