Hmmm in hindsight this is logical, you got 2 kidneys of a certain size. Expected do 1 job together. And since biology doesn't like wastefulness (as it cost ener

Hmmm in hindsight this is logical, you got 2 kidneys of a certain size. Expected do 1 job together. And since biology doesn't like wastefulness (as it cost energy, room, and nutrients to maintain) the kidneys are dimensioned to a safe/good size. Now when you remove 1, the other one has to do twice the job. Possibly severely dipping under the safe size. In short, redundancy != excess