The US have literal tons of lunar soil and rock samples. Why does China want or need the Chang'e 5 mission to return soil from the moon?

美国已经有好多吨的月壤和岩石样本了。为什么中国还要发起嫦娥5号任务去月球自己带回月壤呢?



(当年美国赠送的“国礼”——放大镜下的1克月岩。)