1) In general, the blood money for a female is less than a male because (historically in most societies) the financial loss of a male dying is more than a female dying because men are usually the breadwinners and are obligated to provide for their families.
2) Yes it applies to all societies without any exceptions.
3) It’s about the potential loss. If this fetus would have lived, and he would he a male, in the future he would bring in more money (on average) to the family.