What process is responsible for creating magnetic changes along mid ocean ridges

Witch one is it soo it the the question b.a,b,c,d

:calculate the sum of the interior angles of a 13-sided polygon.

How did the environment influence settlement patterns in colonial america? * 1 point a. early settlers stayed near rivers for farmland and transportation b. early settlers stayed in hilly areas to avoid frequent floods in coastal areas c.early settlers quickly moved to the mountains to avoid hot summers d. early settlers only lived on coastal islands to prevent indian attacks