Answer:
Energy
Explanation:
An energy pyramid shows the amount of energy available at each feeding level in an ecosystem.
A cephalopod is a predatory-like mollusk of the large molluscan class of Cephalopodan animals. This includes cuttlefish, octopus, squid, and/or nautilus. They are animals that live in the ocean. Additionally they eat foods like fish and jellyfish on regular and customary occasions. They sometimes possess cannibalism by eating their own species, which is absolutely crazy. Anyways, I hope that this has helped you today.. :)
All of these are essential to survive
Oxygen is the correct answer !
C hope it helps you. Thanks and have a great day