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प्रश्न
Higher Order Thinking Skill.
How does a fish manage to rise up and move down in water?
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उत्तर
Fish has an internal swim bladder which is filled with gas. When it needs to rise or descend, it changes the volume and its density by filling this bladder with oxygen collected from the surrounding water through gills. When the bladder is filled with oxygen gas, the fish has a greater volume, with minimal increase in weight. When the bladder is expanded, it displaces more water and so experiences a greater force of buoyancy.
When the bladder is completely inflated, the fish has maximum volume and is pushed to the surface. When the bladder is completely deflated, the fish has minimum volume and sinks to the ocean floor.
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