A、The two sides of their brain develop simultaneously. B、They are better able to adapt to the surroundings. C、Their bones mature

A scientific team is studying the thinking ability of eleven-and-a-half-month-old children. The test is a simple one. The baby watches a sort of show on a small stage.
    In Act I of the show, a yellow cube is lifted from a blue box and moved across the stage. Then it is returned to the box. This is repeated six times. Act II is similar, except that the yellow cube is smaller. Baby boys do not react at all to the difference in the size of the cube, but girls immediately become excited.
    The scientists interpret the girls’ excitement as meaning they are trying to understand what they have just seen. They are wondering why Act II is odd and how it differs from Act I. In other words, the little girls are reasoning.
    This experiment certainly does not definitely prove that girls start to reason before boys. But it provides a clue that scientists would like to study more carefully. Already it is known that bones, muscles, and nerves develop faster in baby girls. Perhaps it is early nerve development that makes some infant girls show more intelligence than infant boys.
    Scientists have also found that nature seems to give another boost to girls. Baby girls usually talk at an earlier age than boys do. Scientists think that there is a physical reason for this. They believe that the nerve endings in the left side of the brain develop faster in girls than in boys. And it is this side of the brain that strongly influences an individual’s ability to use language and remember things.
9. What is the difference between Act I and Act II in the test?
10. How do the scientists interpret their observation from the experiment?
11 . What does the speaker say about the experiment?
12. According to scientists, what is another advantage given to girls by nature?