Final answer:
Between the first and last note of a perfect fourth, there are five semitones.
Step-by-step explanation:
The question pertains to the interval of a perfect fourth in music theory. A perfect fourth spans five semitones. For example, from the note C to the note F is a perfect fourth. C to C-sharp is one semitone, C-sharp to D is the second, D to D-sharp is the third, D-sharp to E is the fourth, and E to F is the fifth semitone. This interval is commonly found in various musical scales and is a fundamental part of harmony and chord structures.