Answer: Characteristics: The fins are supported by rays, as the name indicates. In contrast to the cartilaginous fish they have a rigid skeleton. The swim bladder is also a unique feature of most ray-finned fish, enabling them to maintain buoyancy as they move up or down in the water.
I would go for D or A! :)
The answer is d. prevention of muscle strains. Other benefits
of flexibility are Joint health, prevention of low back pain injuries, temporary
reduction of post-exercise muscle soreness, relief of aches and pains, relief
of muscle cramps, maintenance of good posture and balance, relaxation.