The human body is amazing. But there seems to be some evolutionary changes that appear to not make sense regarding redundancy.
While not necessarily the primary reason for their existence, the human body has a great deal of redundancy.
- Two legs
- Two ears
- Two nostrils
- Two lungs
- Two kidneys
- Two sets of teeth
- A very large liver that can work in part.
- Two brain hemispheres that can (to some degree) do the work of the other.
- An appendix that is not critical.
But why do we not have two hearts? It would seem like a good idea to have two smaller hearts, together they work above optimally, but survival would be possible with one.