is what makes a note played on a flute, which produces relatively pure tones, sound different from the same note played on an oboe, which produces very complex sounds. a Frequency b Pitch c Loudness d Timbre

D- TIMBRE

Explanation:

TIMBRE is what makes a note played on a flute or musical instrument have a different sound from another when they sing the same note which produce complex sounds. in another term timbre is what makes a particular musical sound have a different sound from another or the characteristic quality of tone that makes two voices or sounds different, Thereby making the quality of a sound unique.

Timbre can help to distinguish one sound from any other sound.

well, there are a lot of places we get information about earth from. like science classes, websites, books, newspapers, etc.