Which organ is affected in cirrhosis?

Cirrhosis primarily affects the liver, which is a vital organ responsible for a variety of functions, including detoxification of harmful substances, protein synthesis, and the production of biochemicals necessary for digestion. In cirrhosis, the healthy liver tissue is gradually replaced by scar tissue, which impairs the liver's ability to function properly. This scarring can be caused by factors such as chronic alcohol consumption, hepatitis infections, and fatty liver disease, leading to complications like portal hypertension, liver failure, and an increased risk of liver cancer.

The other organs mentioned in the choices do not experience the direct pathological changes associated with cirrhosis. While conditions affecting the liver can sometimes lead to complications that impact other organs (such as kidney function due to fluid overload or issues with digestion that might involve the pancreas), these organs themselves are not the primary sites affected by the cirrhotic process. Thus, the liver is the correct answer, as it is the organ specifically involved in cirrhosis.