What is the name of the muscular organ that pumps blood around the body?

The muscular organ that pumps blood around the body is the heart. This organ is a vital component of the circulatory system, responsible for maintaining blood circulation throughout the body. The heart contracts rhythmically to create pressure that pushes blood into the arteries, delivering oxygen and nutrients to cells while also facilitating the removal of carbon dioxide and waste products.

The other choices serve different functions in the body. The lungs are responsible for gas exchange, allowing oxygen to enter the blood and carbon dioxide to be expelled. The kidneys filter blood to remove waste and excess substances from the body, producing urine. The liver has various functions, including detoxification, synthesis of proteins, and production of biochemicals necessary for digestion. Only the heart specifically fulfills the role of pumping blood, which makes it the correct answer.