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What is Excitable tissue at rest is least permeable to and explain in detail?
Points to note
-        Concentration of ions

Na+ concentration higher in ECF 
K+ concentration higher in ICF 
Cl- concentration higher in ECF

-        K+ leak channels allow K+ to move from ICF to ECF

Na+ is prevented from entering the cell.

Thus diffusion is highest for K+, then Cl- and least for Na+, when the cell is at rest.