【李永乐老师】上帝是左撇子吗？什么是宇称不守恒？

Picked video by video from 李永乐老师 (mixed channel): title plainly names a teaching subject. Channel transcript sample: All three samples lack transcripts, so no direct evidence of teaching substance could be verified, but prior title-sample verdict and channel pattern support a 'pick' classification for video-by-video review.

A 17-minute video from 李永乐老师: “【李永乐老师】上帝是左撇子吗？什么是宇称不守恒？”.

Video by 李永乐老师, played through YouTube's embedded player.