Answer:
The finding that Identical twins who are reared apart tends to have the similar IQ scores will support his argument most strongly.
Step-by-step explanation:
According to the researches it has been found out that the Identical twins who are reared apart tends to have the similar IQ scores.
Here,
The twins have the same heredity i.e having the same genes and the similar environment for the birth and living.
Hence,
The finding that Identical twins who are reared apart tends to have the similar IQ scores will support his argument most strongly.