Final answer:
In a bony fish with a 2-chambered heart, blood gets back to the heart through systemic circulation. The blood flows from the heart to the gills for oxygenation, then continues through the body before returning to the heart.
Step-by-step explanation:
Blood in a bony fish with a 2-chambered heart gets back to the heart through a process called systemic circulation. The blood flows from the heart to the gills, where gas exchange occurs and the blood is re-oxygenated.
Then, the blood continues through the rest of the body before returning back to the heart. This unidirectional flow of blood ensures that oxygenated and deoxygenated blood circulates through the fish's systemic circuit.