Hint: An octopus is an invertebrate animal, meaning it lacks a spine. An octopus, like squid and cuttlefish, is a type of cephalopod. They are among the most intelligent invertebrates.
The term octopus refers to approximately 300 species of soft-bodied, eight-limbed mollusks of the order Octopoda. The order is classified as Cephalopoda, along with squids, cuttlefish, and nautiloids. Cephalopod, any member of the phylum Mollusca's class Cephalopoda, a small group of highly advanced and organized marine animals. An octopus, like other cephalopods, is bilaterally symmetric, with two eyes and a beak, and its mouth at the center of the eight limbs.
Octopuses can squeeze through small gaps due to their soft bodies' ability to rapidly change shape. They swim with their eight appendages trailing behind them. By expelling a jet of water, the siphon is used for both respiration and locomotion. Octopuses are among the most intelligent and behaviorally diverse invertebrates, with a complex nervous system and excellent vision.
Octopuses live in a variety of ocean environments, including coral reefs, pelagic waters, and the seafloor; some live in the intertidal zone, while others live at abysmal depths. Most species grow quickly, mature, and live for a short time.
Expulsion of ink, use of camouflage and threat displays, the ability to jet quickly through the water and hide, and even deception are all strategies used to defend themselves against predators. Although all octopuses are venomous, only the blue-ringed octopuses are known to be lethal to humans.
Thus, Octopus belongs to a class of Cephalopoda.
Octopuses have three hearts: one that circulates blood throughout the body and the other two that supply blood to the gills. The reason for their impressive cardiac hardware is most likely due to their blood's unusual composition.