The molecule that is the energy coin of a cell is:

option a is correct i.e.

only sodium ions can pass through the membrane.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

The right answer is b hydrogen bonds!

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The correct answer:   [c]:   "cell phone call" .