How does a swim bladder help the ray-finned fishes maintain buoyancy?A. Gas is added to the bladder as the fish's depth increases. B. It removes oxygen from the water and stores it. C. It removes water from the digestive tract. D. It adds and removes salt from the water stored in the bladder, which changes its density and thus its buoyancy. E. Gas is removed from the bladder as the fish's depth increases.

A. Gas is added to the bladder as the fish's depth increases.

Explanation:

The swim bladder is a gas-filled organ localized in the dorsal region of Osteichthyes (bony fish) that allows them to regulate buoyancy, thus maintaining water depth without swimming. Since the swim bladder localizes in the dorsal region, it also functions as a stabilizing organ. This organ is composed of two sacs whose walls contract and expand in response to water pressure. The swim bladder contains an oval window that enables to adjust buoyancy in order to maintain a constant depth, or to ascend or descend in a wide range of water depths.

oceans

indian ocean

pacific ocean

atlantic ocean

arctic ocean

southern ocean