Why would a fish that lives in the bathypelagic zone lack a swim bladder, and what adaptations would it maintain neutral buoyancy? -due to the high pressure; gulping air - due to the high pressure; storing extra lipids -due to the low water temperature; gulping air - due to the low water temperature; storing extra lipids

The answer is Due to the low water temperature; storing extra lipids. Fish in these regions are not bony fish (Bony fish are found in epipelagic and mesopelagic). Fish in this region are usually fish such as sharks that have lighter skeletons and have oils in their livers (which is lighter compared to water) to maintain bouyancy. The extra lipids is also an adaptation to keep them warm in the cold depths of the seas. Their skeleton is lighert because it is mainly composed of cartilage.