Concentration and regeneration in supernatural powers in humans

                     Concentration 

concentration is the abundance of a constituent divided by the total volume of a mixture. 
Several types of mathematical description can be distinguished: 
mass concentration, molar concentration, number concentration, and volume concentration.
A concentration can be any kind of chemical mixture, but most frequently solutes and solvents in solutions. 
The molar (amount) concentration has variants such as normal concentration and osmotic concentration.

Regeneration

The power of regeneration allows the user to be able to heal themselves quickly. 

It is also extremely difficult for these people to die. 

The only way they can be killed is if their head is destroyed, so they don't have the mental ability to force their body to recover. 

This power is becoming less common due to modern medicine making it less necessary.

These people usually discover their powers after a failed suicide event or what would have been a fatal accident.

 They believe they should be dead but they see their body healing before their very eyes, and they realize what they are. 

They will then attempt every way to destroy themselves until they come to terms with the fact that they cannot die.

 After this point, they take one of two paths. 

They either will try to help others by going into dangerous situations, or they will become criminals because they know they can get away with whatever crime they have committed.

The downside of this power is that usually, the person will feel all of the pain associated with their injuries, but sometimes the people are too distraught to notice the pain and continue to harm themselves.