Jumping beans are actually seeds in which contain moth larva whose acting causes the seeds to jump.
答案中说“in which” should be “which“,说which在从句中作主语时候前面不能加介词
但是另一句话
It was an agreement the details of which could not be altered.
却明明在which前面加了 of阿
还有
The metaphors we use routinely are the means by which we describe our every day experiences.
都在which前面加了介词阿
