Practice question

Go with B — Amplitude of action potential. Within Action potential, that statement lines up with the standard definition and the usual exam wording you’ll see. In plain terms, the functional job described in the stem is exactly what Amplitude of action potential does in Action potential. Holding that picture in mind makes Amplitude of action potential feel natural rather than something you only memorise. Link the term to a real body example (organ, tissue, or ion flow) so the idea stays concrete under exam pressure. A short mental diagram helps — start from stimulus or structure, follow the pathway, and stop at the functional result described by Amplitude of action potential.