Tag : Turbidity

The respiratory system Oxygen and carbon dioxide dissolve in water, and most fishes exchange dissolved oxygen and carbon dioxide in water by means of the gills. The gills lie behind and to the side of the mouth cavity and consist of fleshy filaments supported by the gill arches and filled with blood vessels, which give gills a bright red colour. Water taken in continuously through ..

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Sand No Sand – No Civilisation Sand is a benign substance that resides in the back of our minds. For most of us, it holds no more day-to-day interest than the rocks and roads – and the other physical aspects of our environment. We know that it exists but it hardly warrants a thought. But, ..

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