OBJECTIVE LIFE SCIENCE
ANIMAL PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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pressure decreases and water into the mouth
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pressure increases and water out of the mouth
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volume decreases pushing water out of the mouth
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volume increases allowing water into the mouth
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Detailed explanation-1: -Fish take water into their mouth, passing the gills just behind its head on each side. Dissolved oxygen is absorbed from-and carbon dioxide released to-the water, which is then dispelled. The gills are fairly large, with thousands of small blood vessels, which maximizes the amount of oxygen extracted.
Detailed explanation-2: -Buccal pumping (active ventilation) occurs when a fish pumps water through its mouth and over its gills. The term draws its name from the buccal cheek muscles with which they do this.
Detailed explanation-3: -Mouth & Opercula Alternate opening of the mouth and two flaps of skin that cover the gills called the opercula (singular: operculum) helps to force water across the gill surface = ventilate the gas exchange surface.