The correct options are
A Smell
C Hearing
∙ The profundal zone is dimly lit and cold. Most of the animals that live here are scavengers (animals that eat dead organisms) and predators (animals that hunt other animals). For example, crustaceans, crabs, fishes like eels, snails, turtles, etc. They adapt themselves by feeding on dead animals that settle down.
∙ Mud of the bottom floor, tiny particles of dead and decaying matter of plants and animal bodies make the water very turbid. Hence the bottom dwellers, rely mostly on sense of smell and hearing to acquire their food.