What initiates the generation of a nerve impulse?

Nerve impulse initiates with the movements of

Consider the statements as True/False:
$I$. The axoplasm inside the axon contains a high concentration of $K^{+}$ and negatively charged proteins.
$II$. The axoplasm inside the axon contains a low concentration of $Na^{+}$.
$III$. The fluid outside the axon contains a low concentration of $K^{+}$.
$IV$. The fluid outside the axon contains a high concentration of $Mg^{++}$ and negatively charged proteins.
The correct option is:

$A$ nerve impulse is generated in a nerve fiber when the membrane becomes more permeable to:

During the conduction of a nerve impulse along a neuron,what is the nature of the electrical charge on the inner side of the plasma membrane?

The conduction of nerve impulse is a