Explain how fish maintain buoyancy?

Most fish (especially the "Bony fish") achieve neutral buoyancy through a sac called the swim bladder in there body of which is filled with air, not much but it'a just enough to keep then a float. The fish can control this organ, and using that they can fill or release air to allow them to rise or sink.

Cartilaginous fish however, do not have a swim bladder.

hope this helps :)

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves