LIFE SCIENCE

Detailed explanation-1: -The swim bladder is a gas-filled organ. This organ contributes to the ability of a fish to control its buoyancy which helps to stay at its current water depth without having to waste energy in swimming. The swim bladder is evolutionarily homologous to the lungs.

Detailed explanation-2: -The gas bladder (also called a swim bladder) is a flexible-walled, gas-filled sac located in the dorsal portion of body cavity. It controls the fish’s buoyancy and in some species is important for hearing.

Detailed explanation-3: -A swim bladder is just an expandable sac, like a human lung. To reduce its overall density, a fish fills the bladder with oxygen collected from the surrounding water via the gills. When the bladder is filled with this oxygen gas, the fish has a greater volume, but its weight is not greatly increased.