eating foods high in protein at a young age having a brother or sister with blue eyes being overexposed to the Sun at a young age receiving a gene for blue eyes from each parent
What causes a person to have blue eyes?

Options:
- eating foods high in protein at a young age
- having a brother or sister with blue eyes
- being overexposed to the Sun at a young age
- receiving a gene for blue eyes from each parent

receiving a gene for blue eyes from each parent