The arrival of the action potential in a presynaptic knob initiates quantal release of neurotransmitter by influx of Ca
This outcome reflects core biological organization, where structure-function relationships govern cellular processes. Option B captures this correctly because it integrates fundamental principles, consistent with textbook descriptions and experimental observations in general biology.
Ref: Campbell et al., Biology, 11th Edition, Chapter 2, Chemical Basis of Life, discusses fundamental biological principles and molecular organization providing broad foundation for life sciences understanding.
