Question

during the rising phase of an action potential, which ion channels open?
voltage - gated sodium channels
voltage - gated potassium channels
ligand - gated calcium channels
chloride leak channels

Explanation:

During the rising - phase of an action potential, the membrane potential depolarizes rapidly. This is due to the opening of voltage - gated sodium channels, which allow a large influx of sodium ions into the cell.

Answer:

Voltage - gated sodium channels