which instrument is played by moving a slide back and forth? trombone sousaphone french horn

which instrument is played by moving a slide back and forth? trombone sousaphone french horn
Answer
Brief Explanations:
The trombone is played by moving its slide back and forth to change the pitch. The sousaphone uses valves and the French - horn uses rotary valves or piston valves, not a slide mechanism.
Answer:
A. Trombone