A real answer transposes literally, keeping every interval of the subject
and leaving the key where the interval puts it. A tonal answer counts scale
degrees instead, so the answer stays in the key: every interval keeps the
number of degrees it spanned in the subject, and only its quality changes as
the key's own pattern of steps and half steps asks — a major third answered by
a minor one.
How an imitation answers the voice it follows.
A
realanswer transposes literally, keeping every interval of the subject and leaving the key where the interval puts it. Atonalanswer counts scale degrees instead, so the answer stays in the key: every interval keeps the number of degrees it spanned in the subject, and only its quality changes as the key's own pattern of steps and half steps asks — a major third answered by a minor one.