What type of family is thought to be the oldest form of the family?
A family consisting of two married adults, along with their offspring, usually living in a private and separate dwelling is the type of family thought to be the oldest family.
What is common among most legal systems regarding property?
The common among most legal systems regarding property is the will, or testament ,that specifies the descendant's wishes as to such distribution ,but a surviving spouse or offspring may contest what appear to be unreasonable or inequitable provisions. There are also laws that recognize family claims in the event that proper is left intestate.