Why do you “see stars” when you hit the back of your head?

Well you see if you dont follow ur parent's expectations or rule you're going to get a beat

1. b vitamins2. vitamin k3. vitamin d4. examples are walnuts, seeds, tofu5.  total fat, saturated fat, trans fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, protein, vitamin a, vitamin c, calcium, and iron.6. 11257. they have to contain reliable information8. less than 10%  9. i didnt read the course so im not surehope that : p