Final answer:
Life estates commonly created by law include common-law and natural rights related to personal freedoms and family rights, as well as usufruct rights in horticultural societies where land use is allocated communally.
Step-by-step explanation:
The most common life estates created by law or statute are those rights "retained by the people," which include common-law and natural rights. These rights, inherited from English legal traditions, encompass a wide array of freedoms that aren't explicitly mentioned in the federal constitution, such as the right to marry, seek employment, pursue education, and raise a family. Additionally, in some societies, particularly horticultural ones, land is held under usufruct rights. Here, land is not owned privately but allocated by family heads or village leaders, allowing individuals the right to use but not own or sell the land. This practice ensures the passing down of rights to use certain plots through familial lines or is provided to newcomers as a gesture of community support.