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In cold weather, aquatic animals survive even when water to the top layer of the lake freezes into ice because.(a) they can breathe in ice (b) they have enough of accumulated oxygen inside them (c) their body structure is such that they can survive without oxygen. (d) water has highest density of 4°C so underneath the top layer of ice there is layer of water |
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Answer» (d) water has highest density of 4°C so underneath the top layer of ice there is layer of water. Explanation: In cold countries, when the temperature of fresh water reaches 4°C, the layers of water near the top in contact with cold air continue to lose heat energy and their temperature falls below 4°C. On cooling below 4°C, these layers do not sink but may rise up as fresh water has a maximum density at 4°C. Due to this, the layer of water at 4°C remains at the bottom and above this layers of water 3°C, 2°C, 1°C and 0°C are formed. Because ice is a poor conductor of heat, it does not absorb heat energy from the water beneath the layer of ice which prevents the water freezing. Thus, aquatic creatures survive in such places. |
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