Final answer:
The movement of electrical impulses along the plasma membrane in an animal's axons is known as action potential, a self-propagating wave of electrical activity crucial for neuron communication. The correct answer is option d.
Step-by-step explanation:
The movement of electrical impulses along the plasma membrane usually occurring in an animal's axons refers to the action potential. An action potential is initiated when a neuron receives a chemical signal or stimulus that causes a change in the electrical gradient across the neuron's plasma membrane. This leads to the sequential opening and closing of voltage-gated and ligand-gated ion channels along the axon, propagating the electrical impulse. When the axon's membrane becomes permeable to Na+ ions due to a stimulus, a depolarization occurs, quickly followed by a repolarization when the membrane becomes impermeable to Na+ and allows the exit of K+ ions.
The process of depolarization and repolarization moves down the axon, creating a self-propagating wave of electrical activity. This electrical signal is crucial for neuron-to-neuron communication and for the control of muscles and glands. Options such as graded potential, hyperpolarization, and electrical synapse refer to other aspects of neuronal communication but do not specifically describe the movement of the action potential along axons.