What is the correct sequence of events that follows a threshold potential? 1. The membrane depolarizes. 2. Sodium channels open and sodium ions diffuse inward. 3. The membrane repolarizes. 4. Potassium channels open and potassium ions diffuse outward.

2,1,4,3

Explanation:

The threshold potential is the minimum or critical level of the potential of the membrane that must be reached in order to generate an action potential.

The action potential in a neuron is generated when the resting potential that is - 70mv changes from its resting potential to a more positive value - 55mv called threshold potential.

The resting potential from - 70mv to - 55mv changes when the membrane sodium ion channels open which cause the movement of the sodium ions into it which leads to the accumulation of positive ions inside. This state is known as the depolarised state. After this, the potassium ions channels open and the potassium ions move out of the membrane f neuron and the potential again changes from the - 55mv to - 70mv. This state is known as the repolarization state.

Thus, 2,1,4,3 is the correct answer.