Studies have shown that:
A) The intelligence of adopted children is more highly correlated with their biologically unrelated parents than their birth parents.
B) for adults, heritability estimates average around .15 to .20.
C) the scores of fraternal twins reared together are more highly correlated than the scores of identical twins reared apart.
D) as adopted children grow into adulthood, the correlation between their IQ scores and those of their biologically unrelated family members diminishes to zero.