According to the Encyclopedia Britannica, IQ is almost totally a product of inheritance.
I guess someone could be so abused that they were physically damaged to the point that all their development would suffer but given anything like normal upbringing, it is nature not nurture.
On the other hand you could take a person who was born with a very low IQ and no matter how many resources were spent on them they would always have a low IQ.
That is true to a point. It would be more accurate to say that maximum possible IQ is a product of inheritance. The actual IQ is a product of several factors, including nutrition and early intellectual stimulation. Children who are not fed animal protein, for example, have lower IQ.
I would expect that middle class black children, being raised with a similar nutritional and intellectual background, would have a similar IQ as middle class white children. Black children in poor neighborhoods do not receive appropriate nutrition, nor do they receive much intellectual stimulation in the black poverty community.
>>According to the Encyclopedia Britannica, IQ is almost totally a product of inheritance.<<
And that was, indeed, the thinking up until a couple of decades ago. But that thinking has changed, and IQ is now viewed as malleable and heavily influenced by the environment a child encounters when growing up.