What do you think will happen if u certain part of the cell fails to function

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.

Abay where the river empties into the sea

I'm sorry to hear that. i will try to answer your other questions if it is within my ability. : )answers: my favourite colour is black.my favourite food is pasta.my favourite school subject is english, but i do also like lunch time.my least favourite subject is history as well as geography. i have currently garnered a quite equal hatred for both of the subjects.what about you? well, you for the points. : )