Researchers have found that a region of the canary forebrain shrinks during the nonbreeding season and enlarges when breeding season begins. This annual enlargement of brain tissue is probably associated with the annual
A) addition of new syllables to a canary's song repertoire.
B) crystallization of subsong into adult songs.
C) sensitive period in which canary parents imprint on new offspring.
D) renewal of mating and nest-building behaviors.
E) elimination of the memorized template for songs sung the previous year.
Answer: A