Why is it that people have different colors of the black part of the eye?

Question: Why is it that people have different colors of the black part of the eye?
- Keywords:
  eye
Asked by 554bm1926 to Grace on 2 Jun 2019.
- Grace Kago answered on 2 Jun 2019:
  
  Hello!
  The part of the eye that’s different colors is called the iris. The different colors are due to varying amount of melanin pigment-containing cells there (that same chemical that’s responsible for the diversity in our skin colour)!
  The black part in the middle of the iris is called the pupil, and it is a structure that absorbs light hence why it looks dark.

Question: Why is it that people have different colors of the black part of the eye?