Questions: The amplitude of the action potential of a given neuron is - dependent on the magnitude of the incoming stimulus. - always the same regardless of the magnitude of the incoming stimulus. - smaller if the resting potential of the neuron is lower. - larger in response to depolarizing currents of greater magnitude.

The answer is the second one: always the same regardless of the magnitude of the incoming stimulus.

Explanation for each option:

1. Dependent on the magnitude of the incoming stimulus: This is incorrect. The amplitude of an action potential is not dependent on the magnitude of the incoming stimulus. Action potentials follow the "all-or-none" principle, meaning that once the threshold is reached, an action potential of a fixed amplitude is generated.

2. Always the same regardless of the magnitude of the incoming stimulus: This is correct. The amplitude of an action potential is consistent and does not vary with the strength of the stimulus, as long as the stimulus is above the threshold required to trigger an action potential.

3. Smaller if the resting potential of the neuron is lower: This is incorrect. The resting potential of the neuron does not affect the amplitude of the action potential. The action potential amplitude is determined by the properties of the ion channels and the ionic gradients across the membrane.

4. Larger in response to depolarizing currents of greater magnitude: This is incorrect. The amplitude of the action potential does not increase with stronger depolarizing currents. Once the threshold is reached, the action potential generated will have a fixed amplitude.

Summary: The amplitude of the action potential of a given neuron is always the same regardless of the magnitude of the incoming stimulus. This is due to the "all-or-none" nature of action potentials.