Through which of the following . Energy (ATP) is required to transport the ions and why ?
(a) Sodium - potassium pumps
(b) `Na^(+)` channels
(c ) `K^(+) ` channels

Explanation

Sodium - potassium pumps require the energy input to transport `3 Na^(+)` outwards for `2 K^(+)` into the axon because sodium - potassium pump works against the concentration gradient of `Na^(+)` and `K^(+)`, Whereas the `Na^(+) and K^(+)` ion channels transport ions from high to low concentrations, i.e., along the conecntration gradient, that is why energy is not required in them .