[ASalazarMX]

Adding to your question, why did the liver evolve to regenerate while other organs evolved to have spares? What makes it special?

[akiselev]

The liver is responsible for clearing out the majority of toxins and since many of them can cause cell death, the organ needs to be able to regenerate itself.

[riversflow]

I’m guessing it has something to do with the size of a liver. Organs that have spares are relatively small.

[abakker]

Lungs? They’re pretty big. My grandfather lived 60 years with only 1, and it stretched to fill most of his chest cavity.