Final answer:
The statement that sodium ions are primarily responsible for the shift to a positive charge during action potential generation in a neuron is true. Sodium ions enter the neuron and trigger depolarization leading to an action potential.
Step-by-step explanation:
The positive ions that help a neuron shift to a positive charge and generate an action potential are indeed primarily made up of sodium ions (Na+) in the neuron's environment. This statement is true. When a neuron is stimulated, these sodium ions rush into the neuron through channels in the membrane, causing depolarization. If depolarization reaches the threshold, an action potential is triggered and the neuron becomes active. The sodium-potassium pump, which requires energy, helps maintain the resting potential of the neuron by pumping out three sodium ions for every two potassium ions it brings in, thus creating a negative charge inside the neuron and a positive charge outside.