Final answer:
If the scale is changed by transposing, the melody changes.
Step-by-step explanation:
The statement 'If the scale is changed, the melody changes' assumes that the scale is only transposed. In this case, the statement is true. Transposing a scale changes the musical intervals between the notes, which in turn changes the melody. For example, if a melody is originally in the C major scale and it is transposed to the G major scale, the intervals between the notes will change, resulting in a different melody.
Therefore, the correct answer is True.