Fish can adjust their buoyancy with an organ called a swim bladder. The swim bladder is a flexible gas-filled sac; a fish can increase or decrease the amount of gas in its swim bladder so that it stays neutrally buoyant, neither sinking nor floating. Suppose a fish is neutrally buoyant at some depth and then goes deeper. What needs to happen to the volume of air in the swim bladder

Volume needs to increase with increased depth

Explanation:

The pressure on the fish body will increase as the fish dives. This increased pressure will lower the volume of the air bladder roughly along the lines of

PV = nRT

To maintain neutral buoyancy, the bladder volume will have to be increased to displace the same amount of water as before.

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.