The Flynn Effect Refers to the Fact That

The Flynn effect refers to the fact that

A) the closer a genetic relationship between two individuals, the more similar their IQ scores are likely to be.
B) members from certain racial groups on average score lower on intelligence tests than other groups.
C) genes set the upper and lower limit for intelligence, but environment determines where within those limits an individual falls.
D) there has been a gradual increase in the scores on intelligence tests over time.