Question: why can people live with one kidney but not with one lung?

Andrew Fensham-Smith answered on 23 Jun 2015:

People can live with one lung, but they can’t run any marathons. If you have two of it, you can probably live with one! It just means you won’t be as good as a normal person if what you’re doing needs a lot of that organ. So, if you only have one kidney, you should avoid drinking alcohol or doing things which might damage it. If you only have one lung, you won’t be as good at breathing, but you’ll probably survive!