Biological child was given up for legal adoption at birth. Now the child is an adult who reestablishes a relationship with biological mother. Biological mother dies and leaves estate to biological child. Family members accept this development. Grandparent of biological child dies and leaves portion of estate to deceased daughter's heirs. Can granddaughter given up for adoption inherit if will states "legal heirs"?

No, once adopted, they are no longer the legal heir of the formal family.

They can be left things in the will if they are named by name.