Final answer:
The liver is the most likely to bleed profusely if injured, due to its large blood supply and vital functions in digestion and metabolism. It is more vascular than the kidney, stomach, and gallbladder, which makes it prone to severe bleeding.
Step-by-step explanation:
The organ that would be the most likely to bleed profusely if severely injured is the liver. The liver is a highly vascular organ, meaning it has a large supply of blood running through it. It is the largest gland in the body and plays a crucial role in metabolism, digestion by secreting bile, and regulation of various substances in the blood.
In comparison, while the kidney also has a significant blood supply, and the stomach has blood vessels that could cause heavy bleeding, the liver's sheer volume of blood flow means it is prone to more severe bleeding if injured. The gallbladder, on the other hand, is less likely to cause profuse bleeding when compared to the liver, as it is primarily a storage organ for bile rather than a highly vascular tissue.