Most fish do not sink in water because of the presence of swim bladderair bladderair sacsair in spongy bones$?

Most fish do not sink in water because of the presence of swim bladder

1.	Most fish do not sink in water because of the presence of swim bladderair bladderair sacsair in spongy bones$?
A.	I and II are correct
B.	II and III are correct
C.	III and IV are correct
D.	I, II, III and IV are correct
Answer» B. II and III are correct