Two sound notes can be distinguished by their quality, pitch and loudness. Explain which one is the distinguishing factor from the notes emitted by two different tuning forks.

Pitch is the distinguishing factor because the notes emitted by two different tuning forks have different frequencies.
Pure note is produced by a tuning fork without overtones, therefore notes cannot be distinguished from quality.
When tuning forks are struck with same force, the forks produce the sound of same loudness. Hence, notes from two tuning forks also cannot be distinguished from their loudness.