Sharks are fish that live in every ocean except the Arctic which is too cold for sharks. Some sharks even live in freshwater lakes and rivers. There are more than 350 different kinds of sharks, each with their own features. Sharks breathe underwater with gills. A gill is an organ on a fish’s side that helps it to breathe. The gills take in oxygen from the water. Sharks have five to seven gill openings called slits. People have skeletons made of bone. Sharks have skeletons made of cartilage. Cartilage is a strong, rubbery tissue. It helps sharks to bend and swim easily. Most sharks have rounded bodies that narrow at each end. This shape makes their bodies streamlined, and helps them to move quickly through the water. Most sharks have two fins on their backs called dorsal fins. They also have one pair of pectoral fins on their sides. The pectoral fins help the shark to steer and balance as they swim. Sharks have one tail fin that helps the shark move through the water.
1. Sharks live in every ocean except the ___________ ocean. 2. Sharks even live in ______________ lakes and _________. 3. There are more than _____ different kinds of sharks. 4. Sharks breath underwater with _________. 5. Sharks have ___ to ____ openings called _________. 6. Sharks have skeletons made of ____________. 7. Most sharks have two fins on their backs called _________ fins. 8. _____________ fins help the shark to steer and balance as they swim.