Yes, you can! It is possible to live with only one functioning kidney.
https://www.kidney.org/atoz/content/onekidney

But I do not see the point of your analogy. It is true that Bitcoin is one of the most well-known and widely used cryptocurrencies, but comparing it to a kidney seems a bit far-fetched. You could argue that Bitcoin's role in the cryptocurrency world is comparable to a vital organ in the human body, however, the cryptocurrency space is diverse and constantly evolving. So while Bitcoin will probably always have a special place, that does not mean it is the only crucial element in the cryptocurrency world.