Final answer:
Sharks are cartilaginous fish with powerful jaws and specialized teeth for feeding. They have well-developed sense organs and need to swim continuously to stay suspended in the water.
Step-by-step explanation:
Sharks belong to the class of cartilaginous fish and are known for their powerful jaws, multiple rows of sharp teeth, and various adaptations for feeding. They have abrasive skin covered with tooth-like scales called placoid scales. Sharks feed on live prey, either swallowing it whole or tearing it into smaller pieces using their jaws and teeth. Their teeth are specialized according to their diet, with some species having teeth for crushing, gripping, or cutting. Sharks also have well-developed sense organs, including a keen sense of smell, electroreceptors for detecting electromagnetic fields, and a lateral line for detecting movement and vibration in the water. Sharks must continuously swim to stay suspended in the water and ventilate their gills.