Howcome people say tanning ability has to do with hair color and eye color?

I have dark brown hair with dark green eyes and I am so pale and hardly tan... To determine one's skin type they ask eye color and hair color. If all this is true I should be like a type 3.....Does this mean I have more melanin because I never try to actually tan. If I actually tried would I have a more successful chance than someone with light hair and light colored eyes?Howcome people say tanning ability has to do with hair color and eye color?
I am a natural redhead...with green eyes and very pale skin..I burn to a crisp...I avoid the sun.....it hurts too bad to get burnt like that...plus my sister is a blond and had skin cancer on her arm from the sun....Howcome people say tanning ability has to do with hair color and eye color?
i have red hair and blue eyes and i can tan lightly but if i stand in the sun for hours il burn