The heirs to an estate are determined by a clear hierarchy of kinship, ensuring that the estate of a deceased person is distributed to close relatives if there is no valid will. At the top of this hierarchy is the surviving spouse, who is typically entitled to a significant portion of the estate. If there are no surviving children, the spouse may inherit everything; however, the presence of biological children or adopted children can change the distribution, with the estate being divided equally among them and the spouse.