Final answer:
A squid has three hearts that help with oxygenation and blood circulation. The mantle of a squid is a muscular organ responsible for jet propulsion.
Step-by-step explanation:
A squid has three hearts. Two of the hearts are branchial hearts, which pump blood to the gills for oxygenation, and the remaining heart is the systemic heart, which pumps oxygenated blood throughout the body. The three hearts help the squid maintain a constant flow of oxygenated blood to all parts of its body, enabling it to survive in the ocean depths.
The mantle of a squid is a muscular organ located in the posterior part of its body. It surrounds the internal organs, including the gills and the hearts. The mantle is responsible for jet propulsion, allowing the squid to move through the water by forcefully expelling water through a funnel-like structure called the siphon.