Counter current exchange in the fish gill helps to maximise the diffusion.
Diffusion is defined as the movement of individual molecules of a substance through a semipermeable barrier from an area of higher concentration to an area of lower concentration.
Fish transfer oxygen from the sea water to their blood using a highly efficient mechanism called counter current exchange.
Counter current is defined as the transport of heat or chemicals between fluids moving in opposite directions separated by a permeable membrane.
Counter current ensures that there is an oxygen gradient along the entire gill lamallae.
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