Question 24 is based on the passage you have just heard.

听力原文

        Left-handed people can find it inconvenient to do certain things, writing in a notebook, for example. But there are a number of advantages of being left-handed. (22) [Research found that they were over-represented among fighters in combat sports. Left-handed fighters also had higher chances to win.] This confirms the fighter theory. Left-handers may also be better at remembering events. (23) [The explanation is that the two brain spheres of left-handers are more strongly connected.] Being left-handed might be a factor in mathematical ability. (24) [An Italian study found that for simple arithmetic, there was little difference between right- and left-handed performance, but for more difficult problem solving, left-handers won out. No one understands the reason for this.] Left-handed people may think differently. In one study, researchers showed the participants columns of abstract illustrations and asked them which ones they would prefer. Left-handed people were more likely to prefer the images on the left. Right-handed people preferred the ones on the right. Both groups disliked stuff on their opposite side. Left-handers are also over-represented in professional interactive sports. (25) [Researchers have looked at the influence of being left-handed on performance and interactive sports. Those that require the fastest reaction give left-handers the biggest advantage. So, if you have a left-handed child, you should encourage them to play table tennis, baseball and tennis.] Being left-handed maximizes their chances of success in these sports.

24. Why are left-handed people better at solving more difficult problems?（为什么左撇子更擅长解答难题？）

解析：B。录音中间位置提到，左撇子更擅长解答难题，但没人知道这是出于何种原因。故正确答案为B。

错项排除：A项中的genes和C项中的larger brain在录音中无依据，故均可排除。文章中只提到了reason，表示“原因”而不是“推理”，故D项排除。