Your answer will be c. each child receives some traits from each parent
Bony fish belong to Class Osteichthyes, while cartilaginous fish belong to Class Chondrichthyes. Bony fish have a bony skeleton, while cartilaginous fish have one composed mostly of cartilage. Bony fish have body coverings of scales, while cartilaginous fish are covered with dendritical projections (think shark skin).
Bony fish are found in fresh and salt water; cartilaginous fish are found only in salt water. Bony fish have gills covered by an operculum; cartilaginous fish have gill slits. Bony have no eyelids; the cartilaginous fish do. Bony fish have an air-filled swim bladder; cartilaginous fish have an oil-filled liver to keep them bouyant. Hope this helps! Whew!
The organs are known as Vestigial organs. The evolution from land-dwelling animal to the marine animals has led whales as well as dolphins, to lose hind limbs. The pelvic and leg bone serves no purpose in them and just provide the anchorage to muscles

Last option: Preserve an ecosystem

• The establishment of a bird reservation is a way to preserve an ecosystem because reservation provides suitable environment to organism. A healthy ecosystem means large number of biodiversity.