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| Read each sentence and identify the word/phrase that you believe correctly completes the statement. Then, click on the arrow to see if your answer is correct. 1. Vertebrates are those members of the phylum possessing a backbone. 2. The most ancient of living fishes are the jawless fishes, represented by (or ) and . 3. Cartilaginous fishes, sharks and related forms, are characterized by a cartilaginous skeleton and exposed visible on the sides or, in skates and rays, on the surface. 4. Most sharks are carnivorous. One exception is the whale shark, a (or ) feeder. 5. Bony fishes, in contrast to cartilaginous fishes, have a bony skeleton, an covering the gills, and a that controls buoyancy. 6. Locomotion in fishes is mostly the result of undulation of the and tail. In bony fishes the are highly maneuverable, whereas in sharks that have a role in the control of . 7. Oxygen enters the blood in the gills of fishes by its from water. The efficiency of oxygenation is increased by water flowing over the gills in the direction to the blood. 8. Marine fishes live in water saltier than their blood and must therefore control the tendency for water to the body. Cartilaginous fishes solved this problem in part by accumulating . Bony fishes swallow seawater, and their kidneys and excrete excess salts. 9. Fishes feature a variety of sense organs. One, the , detects vibrations in the water. 10. Colored pigments in bony fishes are found in cells called . 11. Fishes migrate to feed and breed. Some, the fishes, breed at sea but migrate to fresh water, whereas the fishes migrate the opposite way. 12. The eggs of most marine fishes develop free in the water. These fishes are known as because the eggs are spawned. Others, mostly cartilaginous fishes, are called if the eggs develop in the female, or if the developing embryo derives nutrition from the walls of the mother's reproductive tract. |