{{B}}pAssAgE thrEE{{/B}}

how Do songBirDs lEArn thEir ComplEx voCAlizAtionsA、thEy inhEritED By thEir pArEnts.B、thEy hAvE this nAturAlly EnCoDED in thEir gEnEs.C、thEy lEArn By listEning to othErs oF thEir kinD、D、thEy lEArn By listEning to othEr kinDs oF BirDs.