A、There are more male geniuses than female geniuses. B、People with better nutrition are much more intelligent. C、Females have we

Geniuses are getting brighter. And at genius levels of IQ, girls are not as far behind boys as they used to be.
    SCIENCE has few more controversial topics than human intelligence—in particular, whether variations in it are a result of nature or nurture, and especially whether such variations differ between the sexes. The mines in this field can blow up an entire career, as Larry Summers found out a few years ago when he spoke of his hypothesis. What he found is that the mathematical aptitude needed for physics and engineering, as well as for maths itself, is rarer in women than in men. He resigned as president of Harvard University shortly afterwards.
    It is bold, therefore, of Jonathan Wai, Martha Putallaz and Matthew Makel, of Duke University in North Carolina, to enter the controversy with a paper that addresses both questions. In this paper, just published in Current Directions in Psychological Science, they describe how they picked out through nearly three decades of standardized tests administered to American high-school students to see what had been happening to the country’s brightest sparks.
    They drew two conclusions. One is that a phenomenon called the Flynn effect applies in particular to the brightest of the bright. The other is that part, but not all, of the historic difference between the brainiest men and women has vanished.
    The three researchers drew their data from Duke University’s Talent Identification Program, TIP, which is designed to pick out especially clever candidates early on: all the participants had scored in the top 5% of ability when confronted with exams designed for much older students. TIP, in turn, draws on three national exams: SAT, EXPLORE and ACT. Altogether, Dr. Wai, Dr. Putallaz and Dr. Makel looked at data from 1.7 million children.
    In the general population boys are well known to do a bit better than girls in maths. Girls, in turn, edge out boys on tests of verbal reasoning. The result is similar overall IQ scores. Among the best young mathematical brains, however, the equality is not appropriate. Here, boys do a lot better at maths than girls—but less better than they used to, as the researchers discovered.
19 What did Larry Summers find out?
20 What is the second conclusion drawn in the paper by three researchers?
21 What did the researchers discover about the best young mathematical brains?