Why do some human traits, such as height and hair color, show a large number of phenotypes?

For your questions it may be because of the climatic changes in your contry.(for eg people from very cold countries would likely be having more white hairs,or people from tropical countries such as India,Pakistan,Iraq etc have brown skin due to the exposure of high heat.)

Dmaybe? i’m one of the dumbest girls out there so not to sure, i think it’s d tho

Ihaven't done that yet, so no idea,but this is not the right place to ask