Answer:
Gallbladder
Step-by-step explanation:
The Pancreas regulates blood sugar by producing insulin. You can live without one, however you would need to be on medicine for the rest of your life and watch very carefully want you eat.
The Lungs exchange carbon dioxide and oxygen in your blood. Without your lungs, your body and brain would not get the oxygen it needs to live.
The Gallbladder helps in the digestion process to break down fatty food. Without a gallbladder, you would need to watch out for fatty foods, but you can live easily without this organ.
The bladder stored urine which contains toxic waste that is filtered by the kidneys. Without a bladder, all the toxic waste would go into your blood stream, causing a massive infection leading to sepsis and death.