A、It required all children to go to school. B、It lowered the age of entering school. C、It raised the age of attending school. D、

A study in Norway has found that students who stayed in school longer than others their age scored higher on intelligence tests.
    In the middle of the 1950s, the government began requiring students to attend school until the age of 16 instead of 14. Communities had almost 20 years to make the change. So some students went to school for 7 years while others went for at least 9 years. This difference gave researchers the chance to see if the additional schooling had any effect on intellectual development. The researchers compared the test results of 107000 young men to their years of school. Taryn Ann Galloway is a researcher at the University of Oslo. She says that students who attended school for 9 years scored 7 points higher than those who attended for 7 years. Those who went for 8 years scored about 4 points higher.
    Another recent study, in the journal Nature, found that IQ scores can rise or fall during the teenage years.
    Q25: What did Norway government do in the middle of 1950s?
    Q26: What did Galloway find in her research?
    Q27: What does the study in the journal Nature suggest?