A fugue begins with the exposition of its subject in one of the voices alone in the tonic key.G. M. Tucker and Andrew V. Jones, "Fugue", in The Oxford Companion to Music, ed. Alison Latham (Oxford and New York: Oxford University Press, 2002). After the statement of the subject, a second voice enters and states the subject with the subject transposed to another key (almost always the dominant or subdominant, with the latter being less common), which is known as the answer. To enable a natural harmonic progression, the answer may also be altered slightly (usually by changing one or a few notes near the beginning). When the answer is an exact transposition of the subject into the new key, the answer is classified as a real answer; alternatively, if the intervals of the subject are altered in any way, the answer is a tonal answer.
A fugue begins with the exposition of its subject in one of the voices alone in the tonic key.G. M. Tucker and Andrew V. Jones, "Fugue", in The Oxford Companion to Music, ed. Alison Latham (Oxford and New York: Oxford University Press, 2002). After the statement of the subject, a second voice enters and states the subject with the subject transposed to another key (almost always the dominant or subdominant, with the latter being less common), which is known as the answer To enable a natural harmonic progression, the answer may also be altered slightly (usually by changing one or a few notes near the beginning). When the answer is an exact transposition of the subject into the new key, the answer is classified as a real answer; alternatively, if the intervals of the subject are altered in any way, the answer is a tonal answer.