When the earth was formed and cooled, why did nickel and iron end up in the center of the earth while basalt and granite ended up in the outer layers

- "the acute form of diverticulitis can manifest itself with one or more severe attacks of infection and inflammation.

the inflammation of diverticulitis can eventually result in a bowel obstruction, which may cause constipation, thin stools, diarrhea, abdominal swelling or bloating, and abdominal pain."