finders keepers
arkansas selfdefence laws
Oregon
There is no known "inventor" of the laws of biological inheritance, like other laws of nature, they were discovered. Mendel is the person you are most likely looking for. For more information, look up Mendelian Laws of Inheritance.
You are not a legal heir-at-law of your in-laws. Your spouse is related to them by blood but you are not. You can check the laws of intestate succession in your state at the related question link below.
You can find out about inheritance laws in 1800 England by going to a law library. Law libraries have archives of all the laws passed each year.
Laws of inheritance evolved from ancient common law that was eventually codified in modern state probate codes.
Laws about inheritance vary depending on the country, so check the laws for your specific country. But in general, it should be possible to decline an inheritance - and sometimes it may be to your advantage to decline it, because receiving the inheritance may come along with certain obligations - such as taxes paid on the inheritance, or conditions imposed by the person who leaves you the inheritance.
You can order a copy or access them from a link on the Arkansas Legislature site.
Gregor Mendel
No. Property that you receive by a will IS an inheritance. Property received from a relative under the laws of intestacy when there was no will is also an inheritance.
A legally adopted child has all the rights of a biological child for purposes of inheritance under the state laws of inheritance and intestacy.
Yes, each state's legislature passes the laws for their state.